MAX1220_10 Datasheet, PDF (31/43 Pages) Maxim Integrated Products – 12-Bit, Multichannel ADCs/DACs with FIFO, Temperature Sensing, and GPIO Ports

12-Bit, Multichannel ADCs/DACs with FIFO,
Temperature Sensing, and GPIO Ports
GPIO Write
Write the command byte 00000010 to indicate a GPIO
write operation. The eight SCLK cycles following the
command byte load data from DIN into the GPIO write
register in the MAX1220. The 16 SCLK cycles following
the command byte load data from DIN into the GPIO
write register in the MAX1257/MAX1258. See Tables 15
and 16. The register bits are updated after the last CS
rising edge.
Table 17. GPIO-Mode Control
CONFIGURATION
BIT
1
1
0
0
WRITE
BIT
1
0
1
0
OUTPUT
STATE
1
0
Three-state
0
GPIO
FUNCTION
Output
Output
Input
Pulldown
(open drain)
GPIO Read
Write the command byte 00000001 to indicate a GPIO
read operation. The eight SCLK cycles following the
command byte transfer the state of the GPIOs to DOUT
in the MAX1220. The 16 SCLK cycles following the com-
mand byte transfer the state of the GPIOs to DOUT in the
MAX1257/MAX1258. See Tables 18 and 19.
DAC Serial Interface
Write a command byte 0001XXXX to the DAC select
register to indicate the word to follow is written to the
DAC serial interface, as detailed in Tables 1, 10, 20, and
21. Write the next 16 bits to the DAC interface register,
as shown in Tables 20 and 21. Following the high-to-low
transition of CS, the data is shifted synchronously and
latched into the input register on each falling edge of
SCLK. Each word is 16 bits. The first 4 bits are the con-
trol bits followed by 12 data bits (MSB first) and 2 don’t-
care sub-bits. See Figures 10–12 for DAC timing
specifications.
Table 18. MAX1220 GPIO Read
DATA PIN
GPIO COMMAND BYTE
DIN
00000001 X X X X
DOUT
00000000 0 0 0 0
DATA BYTE
X
X
GPIOC1
GPIOC0
X
GPIOA1
X
GPIOA0
Table 19. MAX1257/MAX1258 GPIO Read
DATA PIN GPIO COMMAND BYTE
DATA BYTE 1
DATA BYTE 2
DIN
00000001X X XX X X X X X X X X X X X X
DOUT
000000000 0 0 0
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