MAX1258 Maxim Integrated Products, MAX1258 Datasheet - Page 31

• Manufacturer Part Number: MAX1258
• Description: Multichannel ADCs/DACs
• Manufacturer: Maxim Integrated Products

w w w . D a t a S h e e t 4 U . c o m
Table 17. GPIO-Mode Control
Table 18. MAX1220/MAX1221 GPIO Read
Table 19. MAX1257/MAX1258 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/MAX1221. The 16 SCLK cycles follow-
ing the command byte transfer the state of the GPIOs to
DOUT in the MAX1257/MAX1258. See Tables 18 and 19.
DIN
DOUT
DIN
DOUT
CONFIGURATION
DATA PIN
DATA PIN
BIT
1
1
0
0
12-Bit, Multichannel ADCs/DACs with FIFO,
0
0
0
0
GPIO COMMAND BYTE
0
0
0
0
GPIO COMMAND BYTE
______________________________________________________________________________________
0
0
WRITE
0
0
BIT
0
0
1
0
1
0
Temperature Sensing, and GPIO Ports
0
0
0
0
0
0
0
0
OUTPUT
Tri-state
STATE
0
0
0
0
1
0
0
1
0
0
0
X
0
1
0
GPIO Read
(open drain)
FUNCTION
Pulldown
X
0
Output
Output
GPIO
X
0
Input
X
0
DATA BYTE 1
X
0
X
0
X
0
X
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 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.
X
0
X
GPIOC1
X
X
X
DATA BYTE
X
GPIOC0
X
X
X
DATA BYTE 2
X
GPIOA1
DAC Serial Interface
X
X
X
GPIOA0
X
X
X
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