upd70f3017ay Renesas Electronics Corporation., upd70f3017ay Datasheet - Page 396

• Manufacturer Part Number: upd70f3017ay
• Description: V850/sa1tm 32-/16-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

14.4 Operation of Port Function
14.4.1 Writing data to I/O port
(1) In output mode
(2) In input mode
14.4.2 Reading data from I/O port
(1) In output mode
(2) In input mode
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The operation of a port differs depending on whether the port is in the input or output mode, as described below.
A value can be written to the output latch by using a transfer instruction. The contents of the output latch are
output from the pin. Once data has been written to the output latch, it is retained until new data is written to the
output latch.
A value can be written to the output latch by using a transfer instruction. Because the output buffer is off,
however, the status of the pin does not change.
Once data has been written to the output latch, it is retained until new data is written to the output latch.
Caution A bit manipulation instruction (CLR1, SET1, NOT1) manipulates 1 bit but accesses a port in 8-bit
The contents of the output latch can be read by using a transfer instruction. The contents of the output latch do
not change.
The status of the pin can be read by using a transfer instruction. The contents of the output latch do not change.
units. If this instruction is executed to manipulate a port with a mixture of input and output
bits, the contents of the output latch of a pin set in the input mode, in addition to the bit to be
manipulated, are overwritten to the current input pin status and become undefined.
CHAPTER 14 PORT FUNCTION
User’s Manual U12768EJ4V1UD