atmega161-4pi ATMEL Corporation, atmega161-4pi Datasheet - Page 85

• Manufacturer Part Number: atmega161-4pi
• Description: 8-bit Microcontroller With 16k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

1228D–AVR–02/07
• Bits 3..2 EMCUCR – SRW01, SRW00: Wait State Select Bits for Lower Page
The SRW01 and SRW00 bits control the number of wait states for the lower page of the
external memory address space (see Table 27).
Table 27. Wait States
Note:
For further details of the timing and wait states of the external memory interface, see
Figure 50 through Figure 53 for how the setting of the SRW bits affects the timing.
Table 28. Page Limits with Different Settings of SRL2..0
SRWn1
SRL2
0
0
1
1
0
0
0
0
1
1
1
1
1. n = 0 or 1 (lower/upper page)
SRWn0
0
1
0
1
SRL1
0
0
1
1
0
0
1
1
(1)
Wait States
No wait states
Wait one cycle during read/write strobe
Wait two cycles during read/write strobe
Wait two cycles during read/write and wait one cycle before driving
out new address
SRL0
0
1
0
1
0
1
0
1
Page Limits
Lower page = N/A
Upper page = $0460-$FFFF
Lower page = $0460-$1FFF
Upper page = $2000-$FFFF
Lower page = $0460-$4FFF
Upper page = $4000-$FFFF
Lower page = $0460-$5FFF
Upper page = $6000-$FFFF
Lower page = $0460-$7FFF
Upper page = $8000-$FFFF
Lower page = $0460-$9FFF
Upper page = $A000-$FFFF
Lower page = $0460-$BFFF
Upper page = $C000-$FFFF
Lower page = $0460-$DFFF
Upper page = $E000-$FFFF
ATmega161(L)
85