7643 datasheet(353/424 Pages) RENESAS

353 / 424 page

7643 Group

REJ09B0133-0200

APPENDIX

3.3 Notes on use

Rev.2.00

Aug 28, 2006

page 30 of 98

•Use the transfer instructions such as LDA and STA to set the registers: USB interrupt status

registers 1, 2 (addresses 005216, 005316); USB endpoint 0 IN control register (address 005916);

USB endpoint x IN control register (address 005916); USB endpoint x OUT control register (address

005A16). Do not use the read-modify-write instructions such as the SEB or the CLB instruction.

When writing to bits shown by Table 32 using the transfer instruction such as LDA or STA, a

value which never affect its bit state is required. Take the following sequence to change these

bits contents:

(1) Store the register contents onto a variable or a data register.

(2) Change the target bit on the variable or the data register. Simultaneously mask the bit so that

its bit state cannot be changed. (See to Table 3.3.1.)

(3) Write the value from the variable or the data register to the register using the transfer instruction

such as LDA or STA.

•To use the AUTO_SET function for an IN transfer when the AUTO_SET bit is set to 1, set the

FIFO to single buffer mode.

Table 3.3.1 Bits of which state might be changed owing to software write

USB endpoint 0 IN control register

USB endpoint x (x = 1 to 2) IN control register

USB endpoint x (x = 1 to 2) OUT control register

Bit name

IN_PKT_RDY (b1)

DATA_END (b3)

FORCE_STALL (b4)

IN_PKT_RDY (b0)

OUT_PKT_RDY (b0)

FORCE_STALL (b4)

Value not affecting state (Note)

“0”

“1”

“0”

“1”

Note: Writing this value will not change the bit state, because this value cannot be written to the bit by software.

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