MAX1020_12 Datasheet, PDF (31/44 Pages) Maxim Integrated Products – 10-Bit, Multichannel ADCs/DACs with FIFO, Temperature Sensing, and GPIO Ports

10-Bit, Multichannel ADCs/DACs with FIFO,
Temperature Sensing, and GPIO Ports
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 MAX1020. The 16 SCLK cycles following the com-
mand byte transfer the state of the GPIOs to DOUT in the
MAX1057/MAX1058. See Tables 18 and 19.
Table 17. GPIO-Mode Control
CONFIGURATION
BIT
1
1
0
WRITE
BIT
1
0
1
OUTPUT
STATE
1
0
Tri-state
0
0
0
GPIO
FUNCTION
Output
Output
Input
Pulldown
(open drain)
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 10 data bits (MSB first) and 2 don’t-
care sub-bits. See Figures 9–12 for DAC timing
specifications.
If CS goes high prior to completing 16 SCLK cycles, the
command is discarded. To initiate a new transfer, drive
CS low again.
For example, writing the DAC serial interface word 1111
0000 and 1111 0100 disconnects DAC outputs 4
through 7 and forces them to a high-impedance state.
DAC outputs 0 through 3 remain in their previous state.
Table 18. MAX1020 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. MAX1057/MAX1058 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
______________________________________________________________________________________ 31