H8SSLASH2214 datasheet(504/936 Pages) RENESAS

Il numero della parte	H8S/2214

Spiegazioni elettronici	16-Bit Single-Chip Microcomputer H8S Family/H8S/2200 Series

PDF	936 Pages

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Produttore elettronici	RENESAS [Renesas Technology Corp]

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Section 11 Watchdog Timer (WDT)

Rev.4.00 Sep. 18, 2008 Page 444 of 872

REJ09B0189-0400

11.2.4

Notes on Register Access

The watchdog timer’s TCNT, TCSR, and RSTCSR registers differ from other registers in being

more difficult to write to. The procedures for writing to and reading these registers are given

below.

(1) Writing to TCNT and TCSR

These registers must be written to by a word transfer instruction. They cannot be written to with

byte transfer instructions.

Figure 11.2 shows the format of data written to TCNT and TCSR. TCNT and TCSR both have the

same write address. For a write to TCNT, the upper byte of the written word must contain H'5A

and the lower byte must contain the write data. For a write to TCSR, the upper byte of the written

word must contain H'A5 and the lower byte must contain the write data. This transfers the write

data from the lower byte to TCNT or TCSR.

TCNT write

TCSR write

Address: H'FF74

H'5A

Write data

8 7

H'A5

Write data

8 7

Figure 11.2 Format of Data Written to TCNT and TCSR (Example of WDT0)

H8S/2214 Scheda tecnica(PDF) 504 Page - Renesas Technology Corp