20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 61

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

Page Mode, allowing from zero to three automatic wait states for the same-page accesses
in the Page Mode. The third setting selects from five to nine automatic wait states for
memory-write bus cycles. The choices available for the advanced bus wait states are suffi-
cient to allow interfacing to a variety of standard memories for any Rabbit 4000 speed
grade.
When a 16-bit memory is connected to /CS0, the first few instructions must program the
device to operate in 16-bit mode. This code is shown below. This code should be the first
thing executed by your device. Because the processor is fetching bytes from a 16-bit
memory device that is not connected to A0, only one-byte instructions can be used, and
they must occur in pairs.
Chapter 5 Memory Management
ORG
XOR
XOR
LD
LD
SCF
SCF
RLA
RLA
LD
LD
SCF
SCF
ADC
ADC
ADD
ADD
SCF
SCF
ADC
ADC
LD
LD
IOI
IOI
LD
LD
NOP
NOP
0000h
A
A
H, A
H, A
B, A
B, A
A, B
A, B
A, A
A, A
A, H
A, H
L, A
L, A
(HL), B
(HL), B
; a <= 00000000
; h <= 00000000
; a <= 00000001
; a <= 00000010
; b <= 00000010
; a <= 00000101
; a <= 00000111
; a <= 00001110
; a <= 00011100
; a <= 00011101
; l <= 00011101
; two IOIs same as one
; MACR <= 00000010
; dummy memory write (no /WE)
; required delay to start
; up the 16-bit bus
51