Athena III User Manual Rev A.03
www.diamondsystems.com
Page
58
12.3
Page 1 Register Definitions
Page 1, Base + 12
Read/Write
EEPROM / TrimDAC Data Register
Bit No.
7
6
5
4
3
2
1
0
Name
D7
D6
D5
D4
D3
D2
D1
D0
During EEPROM or TrimDAC write operations, the data written to this register will be written to the selected
device.
During EEPROM read operations this register contains the data to be read from the EEPROM and is valid
after EEBUSY = 0.
The TrimDAC data cannot be read back.
D7-0
Calibration data to be read or written to the EEPROM and/or TrimDAC.
Page 1, Base + 13
Read/Write
EEPROM / TrimDAC Address Register
Bit No.
7
6
5
4
3
2
1
0
Name
A7
A6
A5
A4
A3
A2
A1
A0
A7-A0
EEPROM / TrimDAC address.
The EEPROM recognizes address 0
– 255 using address bits A7 – A0. The TrimDAC only recognizes
addresses 0
– 7 using bits A2 – A0. In each case remaining address bits will be ignored.
Page 1, Base + 14
Write
Calibration Control Register
Bit No.
7
6
5
4
3
2
1
0
Name
EE_EN
EE_RW
RUNCAL CALMUX TDACWR
X
X
X
This register is used to initiate various commands related to autocalibration.
EE_EN
EEPROM Enable. Writing a 1 to this bit will initiate a transfer to/from the EEPROM as indicated
by the EE_RW bit. If both EE_EN and TDACWR are
set to ‘1’ then TDACWR is ignored.
EE_RW
Selects read or write operation for the EEPROM:
0 = Write
1 = Read
RUNCAL
Writing 1 to this bit causes the board to reload the calibration settings from EEPROM. If this bit is
set to 1, all other bits written to this register are ignored, however the current value of CALMUX is
preserved.
CALMUX
Calibration multiplexor enable. The cal mux is used to read precision on-board reference voltages
that are used in the autocalibration process. It also can be used to read back the value of analog
output 0.
1 = enable cal mux and disable user analog input channels
0 = disable cal mux, enable user inputs
TDACWR TrimDAC Write. Writing 1 to this bit will initiate a transfer to the TrimDAC addressed by the
register at page 1, base+13. (used in the autocalibration process). If both EE_EN and TDACWR
are set to ‘1’ then TDACWR is ignored.