![](http://datasheet.mmic.net.cn/120000/R5F21388SDFP_datasheet_3573603/R5F21388SDFP_217.png)
R8C/38T-A Group
14. I/O Ports
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0241EJ0010 Rev.0.10
Page 186 of 730
Aug 05, 2011
14. I/O Ports
14.1
Overview
There are 75 I/O ports P0 to P3, P4_3 to P4_7, P5, P6, P7, P8, and P9_0 to P9_5. (P4_3 and P4_4 can be used as
I/O ports if the XCIN clock oscillation circuit is not used. P4_6 and P4_7 can be used as I/O ports if the XIN clock
oscillation circuit is not used.)
If the A/D converter is not used, P4_2 can be used as an input-only port.
Notes:
1. In input mode, whether an internal pull-up resistor is connected or not can be selected by registers PUR0 to
PUR2.
2. Whether the drive capacity of the output transistor is set to low or high can be selected by registers DRR0 to
DRR2.
3. The input threshold value can be selected from three voltage levels (0.35 VCC, 0.50 VCC, and 0.70 VCC) using
registers VLT0 to VLT2.
4. Whether the drive capacity of the output transistor is set to low or high can be selected by registers P1DRR and
P2DRR.
5. When the XCIN clock oscillation circuit is not used, these ports can be used as I/O ports.
6. When the XIN clock oscillation circuit is not used, these ports can be used as I/O ports.
7. When the A/D converter is not used, this port can be used as an input-only port.
Table 14.1
I/O Port Overview
Ports
I/O
Output
Type
I/O Setting
Internal Pull-Up
Resister
Drive Capacity
Switch
Input Level
Switch
P0, P3, P5, P6, P7, P8,
and P9_0 to P9_5
I/O
CMOS3
state
Set in 1-bit units Set in 4-bit units
Set in 4-bit units
Set in 8-bit units
P1, P2
I/O
CMOS3
state
Set in 1-bit units Set in 4-bit units
Set in 1-bit units
Set in 8-bit units
I/O
CMOS3
state
Set in 1-bit units Set in 1-bit units
Set in 1-bit units
Set in 6-bit units
I/O
CMOS3
state
Set in 1-bit units Set in 4-bit units
Set in 4-bit units
I
(No
output
function)
None