Maxim Integrated DS4830A Optical Microcontroller - Manual (Page 47)

DS4830A User’s Guide
47
6.2.2 – DAC Data Registers (DACD0-DACD7)
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Name - - - - DACDx[11:0]
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Access r r r r rw rw rw rw rw rw rw rw rw rw rw rw
BIT NAME DESCRIPTION
15:12 - Reserved. The user should write zero to these bits.
11:0 DACDx *[11:0] DACDx: These bits set the DACx output voltage according to reference selection
and reference value.
DACx Output voltage (in Volts) = (DAC Count / 4095) * Reference Voltage (in Volts)
* ‘x’ = 0 to 7
6.2.3 – Reference Pin Configuration Register (RPCFG)
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Name - - - - - - - - - - - - - - REFB_CFG REFA_CFG
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Access r r r r r r r r r r r r r r rw rw
BIT
NAME DESCRIPTION
15:2 - Reserved. The user should not write to these bits.
1 REFB_CFG REFINB Pin Configuration: Setting this bit to ‘1’ configures the DAC external reference pin
for any DAC4-7 as analog input. PIN 39 is REFINB (Port1.4).
0 REFA_CFG REFINA Pin Configuration: Setting this bit to ‘1’ configures the DAC external reference pin
for any DAC0-3 as analog input. PIN 31 is REFINA (Port2.6).
6.3 – DAC Code Examples
6.3.1 – DAC0 Enabled with Internal Reference and Output Voltage Configured for 50% (1.25V) of Internal
Reference
RPCFG = 0x0000;
DACCFG = 0x0002; //Only DAC0 enabled and internal reference is selected
DACD0 = 0x0800; //DACD0 is set for 50%
6.3.2 – DAC2 Enabled with External Reference And Output Voltage Configured for 25% of External Reference
at REFINA Pin
RPCFG = 0x0001;
DACCFG = 0x0010; //Only DAC2 enabled and external reference is selected
DACD2 = 0x0400; //DACD2 is set for 25%
6.3.3 – DAC6 Enabled with External Reference and Output Voltage Configured for 25% of External Reference
at REFINB Pin
RPCFG = 0x0002;
DACCFG = 0x1000; //Only DAC6 enabled and external reference is selected
DACD6 = 0x0400; //DACD6 is set for 25%