Maxim Integrated MAXQ7667 - Manual (Page 94)

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MAXQ7667 User’s Guide
5.3.4 Port Pin Examples
5.3.4.1 Port Pin Example 1: Driving Outputs on Port 0
move PS0, #000h ; Set the output drive strength to 1 mA (approx)
move PO0, #000h ; Set all outputs low
move PD0, #0FFh ; Set all P0 pins to output mode
5.3.4.2 Port Pin Example 2: Receiving Inputs on Port 0
move PO0, #0FFh ; Set weak pullups ON on all pins
move PD0, #000h ; Set all P0 pins to input mode
nop ; Wait for external source to drive P1
move Acc, PI0 ; Get input values from P0
; (will return FF if no other source
; drives the pins low)
PORT P1
PIN
FUNCTION
TYPE
FUNCTION ENABLED WHEN MULTIPLEXING/PRIORITIZATION
Special
SCLK—Serial Clock, Master
Mode, Output
—
Special
SCLK—Serial Clock,
Slave Mode, Input
—
P1.6/SCLK
Alternate External Interrupt 6, Input (EIE1.6) EX6 = 1
This port pin is defaulted as a weak pullup
input after a reset. If interrupt 14 is enabled,
SCLK is not permitted at this pin.
Special
SYNC—Resets the
Synchronous Timer
(SCNT.8) SSYNC_EN = 1
Special
SS—Slave Select for the SPI,
Input, Slave Mode
(SPICN.0) SPIEN = 1
(SPICN.1) MSTM = 0
(SPICN.2) MODFE = 0
Special
SS—Slave Select for the SPI,
Input, Master Mode
(SPICN.0) SPIEN = 1
(SPICN.1) MSTM = 1
(SPICN.2) MODFE = 1
P1.7/SYNC/
SS
Alternate External Interrupt 7, Input (EIE1.7) EX7 = 1
This port pin is defaulted as a weak pullup
input after a reset. If the SPI is enabled as a
slave, this pin is the slave select input. If the
synchronous timer has SSYNC_EN = 1, the
next rising edge on this pin causes a reset of
the synchronous timer's count and the
clearing of SSYNC_EN. Note that the rising
edge detection is performed by
synchronizing the input to the CPU clock
(after any clock division), and as such a
high-going pulse must be greater than 2x
TCK to be detected.
Table 5-5. Port P1 Pin Special and Alternate Functions (continued)