NEC V850E/PH2, User Manual

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Chapter 20 Port Functions
User’s Manual U16580EE3V1UD00
20.3.16 Port CS
Port CS is a 4-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 CS (PCS).
• Input or output mode can be set in 1-bit units by using the port mode register CS (PMCS).
• Port mode or control mode (for alternate function) can be specified in 1-bit units by using the
port mode control register CS (PMCCS).
Table 20-19: Alternate Function Pins and Port Types of Port CS
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 control bus function only. Reprogramming of port CS to port mode is not possible
in these modes. Reading and writing of the port register PCS and port mode register
PMCS is possible but has no effect. Reading of the port mode control register
PMCCS is possible and the result is always 1BH. Writing of the port mode control
register PMCCS is not possible.
(2) Control registers
(a) Port register CS (PCS)
The PCS register is an 8-bit register that controls reading the pin levels and writing the output
levels of port pins PCS0, PCS1, PCS3 and PCS4.
This register can be read or written in 8-bit or 1-bit units.
Reset input causes an undefined register content.
Figure 20-70: Port Register CS (PCS)
Remark: n = 0, 1, 3, 4
Port Alternate Function Remark Port Type
Port CS PCS0
to
PCS5
CS0
Note
Chip select signal output
Note
1
CS1
Note
CS3
Note
CS4
Note
After reset: Undefined R/W Address: FFFFF008H
7 6 5 4 3 2 1 0
PCS 0 0 0 PCS4 PCS3 0 PCS1 PCS0
PCSn Input/Output Data Control of Pin PCSn
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