NEC V850E/RS1 User Manual page 52

(8) PCM0 to PCM3 (Port CM) ... Bi-directional I/O
Port CM is a 4-bit I/O port for which input and output can be set in 1-bit units.
An on-chip pull-up and Pull-down resistor can be specified for use in 1-bit units using pull-up/ pull-
down resistor option register CM (PUCM, PDCM).
(a) Port mode
PCM0 to PCM3 can be set to input or output in 1-bit units using port mode register CM (PMCM).
(b) Control mode
PCM0 to PCM3 can be set to control modes in 1-bit units using port mode control register CM
(PMCCM).
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- HLDAK (hold acknowledge) ... Output
This is an output pin for the acknowledge signal that indicates the high-impedance status for
the address bus, data bus, and control bus when V850E/RS1 receives a bus hold request.
The address bus, data bus, and control bus are in high impedance while this signal is active.
- HLDRQ (hold request) ... Input
This is an input pin by which an external device requests the V850E/RS1 to release the
address bus, data bus, and control bus release requests. This pin accepts asynchronous
input for CLKOUT. When this pin is made active, V850E/RS1 sets the address bus, data bus,
and control bus to high impedance upon the end of the bus cycle currently being executed,
or immediately if no bus cycle is being executed, and the HLDAK signal is then made active
and the bus is released.
- CLKOUT (clock out) ... Output
This pin outputs internally generated bus clocks.
- WAIT (wait) ... Input
This is the input pin for the control signal used to insert waits into the bus cycle. This pin is
sampled at the falling edge of the clock during the T2 or TW state of the bus cycle.
ON/OFF switching of the wait function is performed with port mode control register CM
(PMCCM).
Chapter 2 Pin Functions
User's Manual U16702EE3V2UD00