Configuration Of Real-Time Output Buffer Registers - NEC V850/SB1 User Manual

(1) Real-time output buffer registers (RTBL, RTBH)
RTBL and RTBH are 4-bit registers that hold output data in advance.
These registers are mapped to independent addresses in the peripheral I/O register area as shown in Figure 13-
2.
If an operation mode of 4 bits × 2 channels is specified, data can be individually set to RTBL and RTBH. The
data of both the registers can be read all at once by specifying the address of either of the registers.
If an operation mode of 8 bits × 1 channel is specified, 8-bit data can be set to both RTBL and RTBH respectively
by writing the data to either of the registers. The data of both the registers can be read all at once by specifying
the address of either of the registers.
Figure 13-2 shows the configuration of RTBL and RTBH, and Table 13-2 shows the operation to be performed
when RTBL and RTBH are manipulated.
Figure 13-2. Configuration of Real-Time Output Buffer Registers
Table 13-2. Operation When Real-Time Output Buffer Registers Are Manipulated
Operation Mode Register to Be Manipulated
4 bits × 2 channels
RTBL
RTBH
8 bits × 1 channel
RTBL
RTBH
Notes 1. Only the bits set in the real-time output port mode (RTPM) can be read. If a bit set in the port mode is
read, 0 is read.
2. Set output data to RTBL and RTBH after setting the real-time output port and before the real-time
output trigger is generated.
(2) Output latch
This is the output latch to which the value set by the real-time output buffer register (RTBL, RTBH) is
automatically transferred when the real-time output trigger occurs. Output latches cannot be accessed.
A port specified as a real-time output port cannot set data to the port output latch. To set the initial values of the
real-time output port, set data to the port output latch in the port mode and then set to the real-time output port
mode (refer to 13.5 Usage).
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CHAPTER 13 REAL-TIME OUTPUT FUNCTION (RTO)
Higher 4 bits
RTBH
Higher 4 bits
RTBH
RTBH
RTBH
RTBH
User's Manual U13850EJ6V0UD
Lower 4 bits
RTBL
Note 1
Read
Lower 4 bits Higher 4 bits
RTBL Invalid
RTBL RTBH
RTBL RTBH
RTBL RTBH
Note 2
Write
Lower 4 bits
RTBL
Invalid
RTBL
RTBL