NEC V850E/PH2, User Manual

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Chapter 20 Port Functions
User’s Manual U16580EE3V1UD00
20.3.13 Port AH
Port AH is a 6-bit I/O port that can be set to input or output mode in 1-bit units.
(1) Functions
• Input/output data can be specified in 1-bit units by using the port register AH (PAH).
• Input or output mode can be set in 1-bit units by using the port mode register AH (PMAH).
• Port mode or control mode (for alternate function) can be specified in 1-bit units by using the
port mode control register AH (PMCAH).
Table 20-16: Alternate Function Pins and Port Types of Port AH
Note: Alternate function not available on
μ
PD70F3447.
Caution: On the
μ
PD70F31187, in single-chip mode 1 or in ROM-less mode, this port has exter-
nal address bus function only. Reprogramming of port AH to port mode is not possi-
ble in these modes. Reading and writing of the port register PAH and port mode
register PMAH is possible but has no effect. Reading of the port mode control regis-
ter PMCAH is possible and the result is always 3FH. Writing of the port mode control
register PMCAH is not possible.
(2) Control registers
(a) Port register AH (PAH)
The PAH register is an 8-bit register that controls reading the pin levels and writing the output
levels of port pins PAH0 to PAH5.
This register can be read or written in 8-bit or 1-bit units.
Reset input causes an undefined register content.
Figure 20-61: Port Register AH (PAH)
Remark: n = 0 to 5
Port Alternate Function Remark Port Type
Port AH PAH0
to
PAH5
A16 to A21
Note
External address bus
Note
1
After reset: Undefined R/W Address: FFFFF002H
7 6 5 4 3 2 1 0
PAH 0 0 PAH5 PAH4 PAH3 PAH2 PAH1 PAH0
PAHn Input/Output Data Control of Pin PAHn
0 Input mode: Low level is input
Output mode: Low level is output
1 Input mode: High level is input
Output mode: High level is output