fmc_adc_100Ms_csr

FMC ADC 100MS/s core registers

Wishbone slave for FMC ADC 100MS/s core

Contents:

1. Memory map summary
2. HDL symbol
3. Register description
3.1. Control register
3.2. Status register
3.3. Trigger configuration
3.4. Trigger delay
3.5. Software trigger
3.6. Number of shots
3.7. Remaining shots counter
3.8. Trigger address register
3.9. Sampling clock frequency
3.10. Sample rate
3.11. Pre-trigger samples
3.12. Post-trigger samples
3.13. Samples counter
3.14. Channel 1 control register
3.15. Channel 1 status register
3.16. Channel 1 gain calibration register
3.17. Channel 1 offset calibration register
3.18. Channel 1 saturation register
3.19. Channel 2 control register
3.20. Channel 2 status register
3.21. Channel 2 gain calibration register
3.22. Channel 2 offset calibration register
3.23. Channel 2 saturation register
3.24. Channel 3 control register
3.25. Channel 3 status register
3.26. Channel 3 gain calibration register
3.27. Channel 3 offset calibration register
3.28. Channel 3 saturation register
3.29. Channel 4 control register
3.30. Channel 4 status register
3.31. Channel 4 gain calibration register
3.32. Channel 4 offset calibration register
3.33. Channel 4 saturation register

1. Memory map summary

H/W Address Type Name VHDL/Verilog prefix C prefix
0x0 REG Control register fmc_adc_core_ctl CTL
0x1 REG Status register fmc_adc_core_sta STA
0x2 REG Trigger configuration fmc_adc_core_trig_cfg TRIG_CFG
0x3 REG Trigger delay fmc_adc_core_trig_dly TRIG_DLY
0x4 REG Software trigger fmc_adc_core_sw_trig SW_TRIG
0x5 REG Number of shots fmc_adc_core_shots SHOTS
0x6 REG Remaining shots counter fmc_adc_core_shots_cnt SHOTS_CNT
0x7 REG Trigger address register fmc_adc_core_trig_pos TRIG_POS
0x8 REG Sampling clock frequency fmc_adc_core_fs_freq FS_FREQ
0x9 REG Sample rate fmc_adc_core_sr SR
0xa REG Pre-trigger samples fmc_adc_core_pre_samples PRE_SAMPLES
0xb REG Post-trigger samples fmc_adc_core_post_samples POST_SAMPLES
0xc REG Samples counter fmc_adc_core_samples_cnt SAMPLES_CNT
0xd REG Channel 1 control register fmc_adc_core_ch1_ctl CH1_CTL
0xe REG Channel 1 status register fmc_adc_core_ch1_sta CH1_STA
0xf REG Channel 1 gain calibration register fmc_adc_core_ch1_gain CH1_GAIN
0x10 REG Channel 1 offset calibration register fmc_adc_core_ch1_offset CH1_OFFSET
0x11 REG Channel 1 saturation register fmc_adc_core_ch1_sat CH1_SAT
0x12 REG Channel 2 control register fmc_adc_core_ch2_ctl CH2_CTL
0x13 REG Channel 2 status register fmc_adc_core_ch2_sta CH2_STA
0x14 REG Channel 2 gain calibration register fmc_adc_core_ch2_gain CH2_GAIN
0x15 REG Channel 2 offset calibration register fmc_adc_core_ch2_offset CH2_OFFSET
0x16 REG Channel 2 saturation register fmc_adc_core_ch2_sat CH2_SAT
0x17 REG Channel 3 control register fmc_adc_core_ch3_ctl CH3_CTL
0x18 REG Channel 3 status register fmc_adc_core_ch3_sta CH3_STA
0x19 REG Channel 3 gain calibration register fmc_adc_core_ch3_gain CH3_GAIN
0x1a REG Channel 3 offset calibration register fmc_adc_core_ch3_offset CH3_OFFSET
0x1b REG Channel 3 saturation register fmc_adc_core_ch3_sat CH3_SAT
0x1c REG Channel 4 control register fmc_adc_core_ch4_ctl CH4_CTL
0x1d REG Channel 4 status register fmc_adc_core_ch4_sta CH4_STA
0x1e REG Channel 4 gain calibration register fmc_adc_core_ch4_gain CH4_GAIN
0x1f REG Channel 4 offset calibration register fmc_adc_core_ch4_offset CH4_OFFSET
0x20 REG Channel 4 saturation register fmc_adc_core_ch4_sat CH4_SAT

2. HDL symbol

rst_n_i Control register:
clk_sys_i fmc_adc_core_ctl_fsm_cmd_o[1:0]
wb_adr_i[5:0] fmc_adc_core_ctl_fsm_cmd_wr_o
wb_dat_i[31:0] fmc_adc_core_ctl_fmc_clk_oe_o
wb_dat_o[31:0] fmc_adc_core_ctl_offset_dac_clr_n_o
wb_cyc_i fmc_adc_core_ctl_man_bitslip_o
wb_sel_i[3:0] fmc_adc_core_ctl_test_data_en_o
wb_stb_i fmc_adc_core_ctl_trig_led_o
wb_we_i fmc_adc_core_ctl_acq_led_o
wb_ack_o fmc_adc_core_ctl_reserved_o[23:0]
wb_stall_o  
Status register:
fmc_adc_core_sta_fsm_i[2:0]
fmc_adc_core_sta_serdes_pll_i
fmc_adc_core_sta_serdes_synced_i
fmc_adc_core_sta_acq_cfg_i
fmc_adc_core_sta_reserved_i[25:0]
 
Trigger configuration:
fmc_adc_core_trig_cfg_hw_trig_sel_o
fmc_adc_core_trig_cfg_hw_trig_pol_o
fmc_adc_core_trig_cfg_hw_trig_en_o
fmc_adc_core_trig_cfg_sw_trig_en_o
fmc_adc_core_trig_cfg_int_trig_sel_o[1:0]
fmc_adc_core_trig_cfg_int_trig_test_en_o
fmc_adc_core_trig_cfg_reserved_o
fmc_adc_core_trig_cfg_int_trig_thres_filt_o[7:0]
fmc_adc_core_trig_cfg_int_trig_thres_o[15:0]
 
Trigger delay:
fmc_adc_core_trig_dly_o[31:0]
 
Software trigger:
fmc_adc_core_sw_trig_o[31:0]
fmc_adc_core_sw_trig_wr_o
 
Number of shots:
fmc_adc_core_shots_nb_o[15:0]
fmc_adc_core_shots_reserved_o[15:0]
 
Remaining shots counter:
fmc_adc_core_shots_cnt_val_i[15:0]
fmc_adc_core_shots_cnt_reserved_o[15:0]
 
Trigger address register:
fmc_adc_core_trig_pos_i[31:0]
 
Sampling clock frequency:
fmc_adc_core_fs_freq_i[31:0]
 
Sample rate:
fmc_adc_core_sr_deci_o[31:0]
 
Pre-trigger samples:
fmc_adc_core_pre_samples_o[31:0]
 
Post-trigger samples:
fmc_adc_core_post_samples_o[31:0]
 
Samples counter:
fmc_adc_core_samples_cnt_i[31:0]
 
Channel 1 control register:
fmc_adc_core_ch1_ctl_ssr_o[6:0]
fmc_adc_core_ch1_ctl_reserved_o[24:0]
 
Channel 1 status register:
fmc_adc_core_ch1_sta_val_i[15:0]
fmc_adc_core_ch1_sta_reserved_i[15:0]
 
Channel 1 gain calibration register:
fmc_adc_core_ch1_gain_val_o[15:0]
fmc_adc_core_ch1_gain_reserved_o[15:0]
 
Channel 1 offset calibration register:
fmc_adc_core_ch1_offset_val_o[15:0]
fmc_adc_core_ch1_offset_reserved_o[15:0]
 
Channel 1 saturation register:
fmc_adc_core_ch1_sat_val_o[14:0]
fmc_adc_core_ch1_sat_reserved_o[16:0]
 
Channel 2 control register:
fmc_adc_core_ch2_ctl_ssr_o[6:0]
fmc_adc_core_ch2_ctl_reserved_o[24:0]
 
Channel 2 status register:
fmc_adc_core_ch2_sta_val_i[15:0]
fmc_adc_core_ch2_sta_reserved_i[15:0]
 
Channel 2 gain calibration register:
fmc_adc_core_ch2_gain_val_o[15:0]
fmc_adc_core_ch2_gain_reserved_o[15:0]
 
Channel 2 offset calibration register:
fmc_adc_core_ch2_offset_val_o[15:0]
fmc_adc_core_ch2_offset_reserved_o[15:0]
 
Channel 2 saturation register:
fmc_adc_core_ch2_sat_val_o[14:0]
fmc_adc_core_ch2_sat_reserved_o[16:0]
 
Channel 3 control register:
fmc_adc_core_ch3_ctl_ssr_o[6:0]
fmc_adc_core_ch3_ctl_reserved_o[24:0]
 
Channel 3 status register:
fmc_adc_core_ch3_sta_val_i[15:0]
fmc_adc_core_ch3_sta_reserved_i[15:0]
 
Channel 3 gain calibration register:
fmc_adc_core_ch3_gain_val_o[15:0]
fmc_adc_core_ch3_gain_reserved_o[15:0]
 
Channel 3 offset calibration register:
fmc_adc_core_ch3_offset_val_o[15:0]
fmc_adc_core_ch3_offset_reserved_o[15:0]
 
Channel 3 saturation register:
fmc_adc_core_ch3_sat_val_o[14:0]
fmc_adc_core_ch3_sat_reserved_o[16:0]
 
Channel 4 control register:
fmc_adc_core_ch4_ctl_ssr_o[6:0]
fmc_adc_core_ch4_ctl_reserved_o[24:0]
 
Channel 4 status register:
fmc_adc_core_ch4_sta_val_i[15:0]
fmc_adc_core_ch4_sta_reserved_i[15:0]
 
Channel 4 gain calibration register:
fmc_adc_core_ch4_gain_val_o[15:0]
fmc_adc_core_ch4_gain_reserved_o[15:0]
 
Channel 4 offset calibration register:
fmc_adc_core_ch4_offset_val_o[15:0]
fmc_adc_core_ch4_offset_reserved_o[15:0]
 
Channel 4 saturation register:
fmc_adc_core_ch4_sat_val_o[14:0]
fmc_adc_core_ch4_sat_reserved_o[16:0]

3. Register description

3.1. Control register

HW prefix: fmc_adc_core_ctl
HW address: 0x0
C prefix: CTL
C offset: 0x0
31 30 29 28 27 26 25 24
RESERVED[23:16]
23 22 21 20 19 18 17 16
RESERVED[15:8]
15 14 13 12 11 10 9 8
RESERVED[7:0]
7 6 5 4 3 2 1 0
ACQ_LED TRIG_LED TEST_DATA_EN MAN_BITSLIP OFFSET_DAC_CLR_N FMC_CLK_OE FSM_CMD[1:0]

3.2. Status register

HW prefix: fmc_adc_core_sta
HW address: 0x1
C prefix: STA
C offset: 0x4
31 30 29 28 27 26 25 24
RESERVED[25:18]
23 22 21 20 19 18 17 16
RESERVED[17:10]
15 14 13 12 11 10 9 8
RESERVED[9:2]
7 6 5 4 3 2 1 0
RESERVED[1:0] ACQ_CFG SERDES_SYNCED SERDES_PLL FSM[2:0]

3.3. Trigger configuration

HW prefix: fmc_adc_core_trig_cfg
HW address: 0x2
C prefix: TRIG_CFG
C offset: 0x8
31 30 29 28 27 26 25 24
INT_TRIG_THRES[15:8]
23 22 21 20 19 18 17 16
INT_TRIG_THRES[7:0]
15 14 13 12 11 10 9 8
INT_TRIG_THRES_FILT[7:0]
7 6 5 4 3 2 1 0
RESERVED INT_TRIG_TEST_EN INT_TRIG_SEL[1:0] SW_TRIG_EN HW_TRIG_EN HW_TRIG_POL HW_TRIG_SEL

3.4. Trigger delay

HW prefix: fmc_adc_core_trig_dly
HW address: 0x3
C prefix: TRIG_DLY
C offset: 0xc
31 30 29 28 27 26 25 24
TRIG_DLY[31:24]
23 22 21 20 19 18 17 16
TRIG_DLY[23:16]
15 14 13 12 11 10 9 8
TRIG_DLY[15:8]
7 6 5 4 3 2 1 0
TRIG_DLY[7:0]

3.5. Software trigger

HW prefix: fmc_adc_core_sw_trig
HW address: 0x4
C prefix: SW_TRIG
C offset: 0x10

Writing (anything) to this register generates a software trigger.

31 30 29 28 27 26 25 24
SW_TRIG[31:24]
23 22 21 20 19 18 17 16
SW_TRIG[23:16]
15 14 13 12 11 10 9 8
SW_TRIG[15:8]
7 6 5 4 3 2 1 0
SW_TRIG[7:0]

3.6. Number of shots

HW prefix: fmc_adc_core_shots
HW address: 0x5
C prefix: SHOTS
C offset: 0x14
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
NB[15:8]
7 6 5 4 3 2 1 0
NB[7:0]

3.7. Remaining shots counter

HW prefix: fmc_adc_core_shots_cnt
HW address: 0x6
C prefix: SHOTS_CNT
C offset: 0x18
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.8. Trigger address register

HW prefix: fmc_adc_core_trig_pos
HW address: 0x7
C prefix: TRIG_POS
C offset: 0x1c
31 30 29 28 27 26 25 24
TRIG_POS[31:24]
23 22 21 20 19 18 17 16
TRIG_POS[23:16]
15 14 13 12 11 10 9 8
TRIG_POS[15:8]
7 6 5 4 3 2 1 0
TRIG_POS[7:0]

3.9. Sampling clock frequency

HW prefix: fmc_adc_core_fs_freq
HW address: 0x8
C prefix: FS_FREQ
C offset: 0x20
31 30 29 28 27 26 25 24
FS_FREQ[31:24]
23 22 21 20 19 18 17 16
FS_FREQ[23:16]
15 14 13 12 11 10 9 8
FS_FREQ[15:8]
7 6 5 4 3 2 1 0
FS_FREQ[7:0]

3.10. Sample rate

HW prefix: fmc_adc_core_sr
HW address: 0x9
C prefix: SR
C offset: 0x24
31 30 29 28 27 26 25 24
DECI[31:24]
23 22 21 20 19 18 17 16
DECI[23:16]
15 14 13 12 11 10 9 8
DECI[15:8]
7 6 5 4 3 2 1 0
DECI[7:0]

3.11. Pre-trigger samples

HW prefix: fmc_adc_core_pre_samples
HW address: 0xa
C prefix: PRE_SAMPLES
C offset: 0x28
31 30 29 28 27 26 25 24
PRE_SAMPLES[31:24]
23 22 21 20 19 18 17 16
PRE_SAMPLES[23:16]
15 14 13 12 11 10 9 8
PRE_SAMPLES[15:8]
7 6 5 4 3 2 1 0
PRE_SAMPLES[7:0]

3.12. Post-trigger samples

HW prefix: fmc_adc_core_post_samples
HW address: 0xb
C prefix: POST_SAMPLES
C offset: 0x2c
31 30 29 28 27 26 25 24
POST_SAMPLES[31:24]
23 22 21 20 19 18 17 16
POST_SAMPLES[23:16]
15 14 13 12 11 10 9 8
POST_SAMPLES[15:8]
7 6 5 4 3 2 1 0
POST_SAMPLES[7:0]

3.13. Samples counter

HW prefix: fmc_adc_core_samples_cnt
HW address: 0xc
C prefix: SAMPLES_CNT
C offset: 0x30
31 30 29 28 27 26 25 24
SAMPLES_CNT[31:24]
23 22 21 20 19 18 17 16
SAMPLES_CNT[23:16]
15 14 13 12 11 10 9 8
SAMPLES_CNT[15:8]
7 6 5 4 3 2 1 0
SAMPLES_CNT[7:0]

3.14. Channel 1 control register

HW prefix: fmc_adc_core_ch1_ctl
HW address: 0xd
C prefix: CH1_CTL
C offset: 0x34
31 30 29 28 27 26 25 24
RESERVED[24:17]
23 22 21 20 19 18 17 16
RESERVED[16:9]
15 14 13 12 11 10 9 8
RESERVED[8:1]
7 6 5 4 3 2 1 0
RESERVED[0:0] SSR[6:0]

3.15. Channel 1 status register

HW prefix: fmc_adc_core_ch1_sta
HW address: 0xe
C prefix: CH1_STA
C offset: 0x38
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.16. Channel 1 gain calibration register

HW prefix: fmc_adc_core_ch1_gain
HW address: 0xf
C prefix: CH1_GAIN
C offset: 0x3c
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.17. Channel 1 offset calibration register

HW prefix: fmc_adc_core_ch1_offset
HW address: 0x10
C prefix: CH1_OFFSET
C offset: 0x40
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.18. Channel 1 saturation register

HW prefix: fmc_adc_core_ch1_sat
HW address: 0x11
C prefix: CH1_SAT
C offset: 0x44
31 30 29 28 27 26 25 24
RESERVED[16:9]
23 22 21 20 19 18 17 16
RESERVED[8:1]
15 14 13 12 11 10 9 8
RESERVED[0:0] VAL[14:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.19. Channel 2 control register

HW prefix: fmc_adc_core_ch2_ctl
HW address: 0x12
C prefix: CH2_CTL
C offset: 0x48
31 30 29 28 27 26 25 24
RESERVED[24:17]
23 22 21 20 19 18 17 16
RESERVED[16:9]
15 14 13 12 11 10 9 8
RESERVED[8:1]
7 6 5 4 3 2 1 0
RESERVED[0:0] SSR[6:0]

3.20. Channel 2 status register

HW prefix: fmc_adc_core_ch2_sta
HW address: 0x13
C prefix: CH2_STA
C offset: 0x4c
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.21. Channel 2 gain calibration register

HW prefix: fmc_adc_core_ch2_gain
HW address: 0x14
C prefix: CH2_GAIN
C offset: 0x50
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.22. Channel 2 offset calibration register

HW prefix: fmc_adc_core_ch2_offset
HW address: 0x15
C prefix: CH2_OFFSET
C offset: 0x54
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.23. Channel 2 saturation register

HW prefix: fmc_adc_core_ch2_sat
HW address: 0x16
C prefix: CH2_SAT
C offset: 0x58
31 30 29 28 27 26 25 24
RESERVED[16:9]
23 22 21 20 19 18 17 16
RESERVED[8:1]
15 14 13 12 11 10 9 8
RESERVED[0:0] VAL[14:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.24. Channel 3 control register

HW prefix: fmc_adc_core_ch3_ctl
HW address: 0x17
C prefix: CH3_CTL
C offset: 0x5c
31 30 29 28 27 26 25 24
RESERVED[24:17]
23 22 21 20 19 18 17 16
RESERVED[16:9]
15 14 13 12 11 10 9 8
RESERVED[8:1]
7 6 5 4 3 2 1 0
RESERVED[0:0] SSR[6:0]

3.25. Channel 3 status register

HW prefix: fmc_adc_core_ch3_sta
HW address: 0x18
C prefix: CH3_STA
C offset: 0x60
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.26. Channel 3 gain calibration register

HW prefix: fmc_adc_core_ch3_gain
HW address: 0x19
C prefix: CH3_GAIN
C offset: 0x64
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.27. Channel 3 offset calibration register

HW prefix: fmc_adc_core_ch3_offset
HW address: 0x1a
C prefix: CH3_OFFSET
C offset: 0x68
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.28. Channel 3 saturation register

HW prefix: fmc_adc_core_ch3_sat
HW address: 0x1b
C prefix: CH3_SAT
C offset: 0x6c
31 30 29 28 27 26 25 24
RESERVED[16:9]
23 22 21 20 19 18 17 16
RESERVED[8:1]
15 14 13 12 11 10 9 8
RESERVED[0:0] VAL[14:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.29. Channel 4 control register

HW prefix: fmc_adc_core_ch4_ctl
HW address: 0x1c
C prefix: CH4_CTL
C offset: 0x70
31 30 29 28 27 26 25 24
RESERVED[24:17]
23 22 21 20 19 18 17 16
RESERVED[16:9]
15 14 13 12 11 10 9 8
RESERVED[8:1]
7 6 5 4 3 2 1 0
RESERVED[0:0] SSR[6:0]

3.30. Channel 4 status register

HW prefix: fmc_adc_core_ch4_sta
HW address: 0x1d
C prefix: CH4_STA
C offset: 0x74
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.31. Channel 4 gain calibration register

HW prefix: fmc_adc_core_ch4_gain
HW address: 0x1e
C prefix: CH4_GAIN
C offset: 0x78
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.32. Channel 4 offset calibration register

HW prefix: fmc_adc_core_ch4_offset
HW address: 0x1f
C prefix: CH4_OFFSET
C offset: 0x7c
31 30 29 28 27 26 25 24
RESERVED[15:8]
23 22 21 20 19 18 17 16
RESERVED[7:0]
15 14 13 12 11 10 9 8
VAL[15:8]
7 6 5 4 3 2 1 0
VAL[7:0]

3.33. Channel 4 saturation register

HW prefix: fmc_adc_core_ch4_sat
HW address: 0x20
C prefix: CH4_SAT
C offset: 0x80
31 30 29 28 27 26 25 24
RESERVED[16:9]
23 22 21 20 19 18 17 16
RESERVED[8:1]
15 14 13 12 11 10 9 8
RESERVED[0:0] VAL[14:8]
7 6 5 4 3 2 1 0
VAL[7:0]