M32C80 Datasheet, PDF (64/352 Pages) Renesas Technology Corp – 16/32-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M32C/80 SERIES

M32C/80 Group
7. Bus
7.2.4 Bus Timing
Bus cycle for the internal memory is basically one BCLK cycle. When the PM12 bit in the PM1 register is
set to "1" (wait state), the bus cycles are two BCLK cycles.
Bus cycles for SFRs are basically two BCLK cycles. When the PM13 bit in the PM1 register is set to "1"
(2 wait states), the bus cycles are three BCLK cycles.
Basic bus cycle for an external space is 2ø (1ø+1ø) to read and to write. Bus cycle is selected by the
EWCRi register (i=0 to 3) from 12 types of separate bus settings and 7 types of multiplexed bus settings.
If the EWCRi04 to EWCRi00 bits are set to "000112" (1ø+3ø), bus cycles are four BCLK cycles.
Figure 7.3 shows the EWCRi register. Figures 7.4 to 7.8 show bus timing in an external space.
External Space Wait Control Register i (i=0 to 3)(3)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
Address
After Reset
EWCR0 to EWCR3 004816, 004916, 004A16, 004B16 X0X0 00112
Bit
Symbol
EWCRi00
Bit Name
EWCRi01
EWCRi02 Bus Cycle Select Bit
EWCRi03
EWCRi04
Function
RW
b4 b3 b2 b1 b0 (1) (2)
0 0 0 0 1: 1φ + 1φ
RW
0 0 0 1 0: 1φ + 2φ
0 0 0 1 1: 1φ + 3φ
0 0 1 0 0: 1φ + 4φ
RW
0 0 1 0 1: 1φ + 5φ
0 0 1 1 0: 1φ + 6φ
0 1 0 1 0: 2φ + 2φ
0 1 0 1 1: 2φ + 3φ
RW
0 1 1 0 0: 2φ + 4φ
0 1 1 0 1: 2φ + 5φ
1 0 0 1 1: 3φ + 3φ
RW
1 0 1 0 0: 3φ + 4φ
1 0 1 0 1: 3φ + 5φ
1 0 1 1 0: 3φ + 6φ
RW
Do not set values other than the above
Nothing is assigned.
(b5) When read, its content is indeterminate.
0: Adds no recovery cycle when
EWCRi06
Recovery Cycle Addition
Select Bit
accessing external space i
1: Adds a recovery cycle when
RW
accessing external space i
Nothing is assigned.
(b7) ^{When read, its content is indeterminate.}
NOTES:
1. The number of bus cycles from "when bus access begins" to "when RD or WR signal becomes "L".
2. The number of bus cycles from "when RD or WR signal becomes "L" to "when it becomes "H".
Figure 7.3 EWCR0 to EWCR3 Registers
Rev. 1.00 Nov. 01, 2005 Page 45 of 330
REJ09B0271-0100