How do I use an external reference on the MAX1343?

The operation of the references used by the MAX1343 depend on the clock mode, type of conversion, and whether the ADC or DAC are in use. Regardless of clock mode, temperature conversions are performed using the internal reference. For all clock modes, the reference source of the MAX1343 can be selected by writing a command byte to the Setup Register. A single byte with the first two bits set to 01 will automatically write the remaining six bits to the Setup Register. The REFSEL[1:0] bits in the Setup Register control the type of reference selected. REFSEL[1:0] = 00 selects the internal reference for both the DAC and ADC. REFSEL[1:0] = 01 selects external single-ended references. REF1 is used for the DAC and REF2 is used for the ADC. REFSEL[1:0] = 10 selects the external reference REF1 for the DAC and the internal reference for the ADC. REFSEL[1:0] = 11 selects the external reference REF1 for the DAC and the external differential reference (REF1 - REF2) for the ADC. To configure both the ADC and the DAC of the MAX1343 for an external reference, send the following command: 01XX01XX

How do I configure the GPIO ports on the MAX1343?

The MAX1343 features four GPIO pins: GPIOA0, GPIOA1, GPIOC0, GPIOC1. To program the GPIO ports, two 16-bit commands are required. The first command goes to the GPIO Configuration register, which sets each port as either a push-pull output, or a tri-state input/open-drain pull-down. The second command goes to the GPIO Write register, which sets the push-pull level, or selects between the tri-state input or open-drain pull-down. To set up GPIOC1 as a logic high output, the following commands must be sent (with /CS toggling between the two 16-bit commands): 0000 0011 1000 0000 0000 0010 1000 0000 In the first command, 0000 0011 is the command byte to access the GPIO Configuration register and 1000 0000 configures GPIOC1 as a push-pull output by writing a '1' to the GPIOC1 bitfield. In the second command, 0000 0010 is the command byte to access the GPIO Write register and 1000 0000 configures GPIOC1 as an output high by writing a '1' to the GPIOC1 bitfield.

How do I set up the DAC output on the MAX1343?

The MAX1343 internal 8-channel DAC needs to be enabled through register commands before the DAC output become active. Each DAC can be turned on individually, or groups of the DAC channels can be enabled with a single command as shown in Table 18 of the datasheet. Sending the command 0001 0000 1111 1111 1111 0010 should power on all DAC channels.