Renesas Single-Chip Microcomputer M34519T-MCU - Manual (Page 26)

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4.3 RAM Backup Mode
In RAM backup mode, the M34519T-MCU operates differently from the actual MCUs. Although the
actual MCU enters RAM backup mode depending on a combination of instructions EPOF and POF,
the M34519T-MCU is placed in RAM backup mode by executing instruction POF only. Instruction
EPOF has no effect on the M34519T-MCU.
Program example 4.1
RC
INY
EPOF
POF
•
•
Program example 4.2
RC
INY
POF
•
•
[Actual MCU]
Placed in RAM backup mode
[M34519T-MCU]
Placed in RAM backup mode
[Actual MCU]
Not placed in RAM backup mode
[M34519T-MCU]
Placed in RAM backup mode
4.4 Port I/O Timings
(1) Port input timings
Port input timings are the same as with actual the MCUs.
(2) Port output timings
When using the M34519T-MCU, output timings are different from those of the actual MCUs,
because the following ports that are configured with the port emulation circuits.
• Ports D0--D5
• Ports P00--P03
• Ports P10--P13
With the actual MCUs, changes occur at the beginning of the T3 state of an output instruction.
With the M34519T-MCU, changes occur at the beginning of the T2 state of the next output
instruction. Figure 4.2 shows the port output timings of the actual MCUs and M34519T-MCU.
For the other ports, the output timings are the same as with the actual MCUs.
Next output instruction Output instruction
System clock
XIN
Ports D, P0, P1
output timings
on actual MCUs
Ports D, P0, P1
output timings of
M34519T-MCU
Figure 4.2 Ports D, P0 and P1 output timings