
CHAPTER 12 REAL-TIME OUTPUT FUNCTION (RTO)
User’s Manual U16541EJ4V0UD
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(1) Real-time output buffer registers 0L, 0H (RTBL0, RTBH0)
The RTBL0 and RTBH0 registers are 4-bit registers that hold preset output data.
These registers are mapped to independent addresses in the peripheral I/O register area.
These registers can be read or written in 8-bit or 1-bit units.
Reset input clears these registers to 00H.
If an operation mode of 4 bits
× 1 channel or 2 bits × 1 channel is specified (RTPC0.BYTE0 bit = 0), data can
be individually set to the RTBL0 and RTBH0 registers. The data of both these registers can be read at once
by specifying the address of either of these registers.
If an operation mode of 6 bits
× 1 channel is specified (BYTE0 bit = 1), 8-bit data can be set to both the RTBL0
and RTBH0 registers by writing the data to either of these registers.
Moreover, the data of both these
registers can be read at once by specifying the address of either of these registers.
Table 12-2 shows the operation when the RTBL0 and RTBH0 registers are manipulated.
0
RTBL0
RTBH0
0
RTBH05 RTBH04
RTBL03
RTBL02
RTBL01
RTBL00
After reset: 00H
R/W
Address: RTBL0 FFFFF6E0H, RTBH0 FFFFF6E2H
Cautions 1. When writing to bits 6 and 7 of the RTBH0 register, always write 0.
2. Accessing the RTBL0 and RTBH0 registers is prohibited in the following
statuses. For details, refer to 3.4.9 (2) Accessing specific on-chip peripheral
I/O registers.
When the CPU operates with the subclock and the main clock oscillation is
stopped
When the CPU operates with the internal oscillation clock
Table 12-2. Operation During Manipulation of RTBL0 and RTBH0 Registers
Read
Write
Note
Operation Mode
Register to Be
Manipulated
Higher 4 Bits
Lower 4 Bits
Higher 4 Bits
Lower 4 Bits
RTBL0
RTBH0
RTBL0
Invalid
RTBL0
4 bits
× 1 channel,
2 bits
× 1 channel
RTBH0
RTBL0
RTBH0
Invalid
RTBL0
RTBH0
RTBL0
RTBH0
RTBL0
6 bits
× 1 channel
RTBH0
RTBL0
RTBH0
RTBL0
Note After setting the real-time output port, set output data to the RTBL0 and RTBH0 registers by the time a real-
time output trigger is generated.