CHAPTER 21 RESET FUNCTION
Page 752 of 920
21.2
Register for Confirming Reset Source
21.2.1
Reset control flag register (RESF)
Many internal reset generation sources exist in the RL78 microcontroller. The reset control flag register (RESF)
is used to store which source has generated the reset request.
The RESF register can be read by an 8-bit memory manipulation instruction.
RESET input, reset by power-on-reset (POR) circuit, and reading the RESF register clear TRAP, WDTRF,
RPERF, IAWRF, and LVIRF flags. To judge the reset source, store RESF register value in the desired RAM, and
use the RAM value for judging.
Figure 21 - 4 Format of Reset control flag register (RESF)
Note 1.
The value after reset varies depending on the reset source. See
Note 2.
The illegal instruction is generated when instruction code FFH is executed.
Reset by the illegal instruction execution not issued by emulation with the in-circuit emulator or on-chip debug
emulator.
Caution 1. Do not read data by a 1-bit memory manipulation instruction.
Caution 2. When enabling RAM parity error resets (RPERDIS = 0), be sure to initialize the used RAM area at data
access or the used RAM area + 10 bytes at execution of instruction from the RAM area.
Reset generation enables RAM parity error resets (RPERDIS = 0). For details, see 24.3.3 RAM parity
error detection function.
Address: FFFA8H
After reset: Undefined
Symbol
7
6
5
4
3
2
1
0
TRAP
0
0
WDTRF
0
RPERF
IAWRF
LVIRF
Internal reset request by execution of illegal instruction
0
Internal reset request is not generated, or the RESF register is cleared.
1
Internal reset request is generated.
Internal reset request by watchdog timer (WDT)
0
Internal reset request is not generated, or the RESF register is cleared.
1
Internal reset request is generated.
Internal reset request t by RAM parity
0
Internal reset request is not generated, or the RESF register is cleared.
1
Internal reset request is generated.
Internal reset request t by illegal-memory access
0
Internal reset request is not generated, or the RESF register is cleared.
1
Internal reset request is generated.
Internal reset request by voltage detector (LVD)
0
Internal reset request is not generated, or the RESF register is cleared.
1
Internal reset request is generated.
Содержание RL78/G1H
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