![background image](http://html2.mh-extra.com/html/rabbit/2000/2000_user-manual_3110256115.webp)
User’s Manual
109
10. I/O B
ANK
C
ONTROL
R
EGISTERS
The pins of Port E can be set individually to be I/O strobes. Each of the eight possible I/O
strobes has a control register that controls the nature of the strobe and the number of wait
states that will be inserted in the I/O bus cycle. Writes can also be suppressed for any of
the strobes. The types of strobes are shown in Figure 10-1. Each of the eight I/O strobes is
active for addresses occupying 1/8th of the 64K external I/O address space.
Figure 10-1. External I/O Bus Cycles
Table 10-1 shows how the eight I/O bank control registers are organized.
Table 10-1. I/O Bank Control Reg (adr IBxCR = 08xh)
Bits 7,6
*
* Total number of external I/O read/write wait states, including the one wait state
that is always present.
Bits 5,4
Bit 3
Bits 2–0
Wait state code
11-1
10-3
01-7
00-15
/IX strobe type
00—chip select
01—read strobe
10—write strobe
11—or of read and
write strobe
1—permit write
0—inhibit write
Ignored
ADDR
T1
Tw
T2
write data
write strobe
read data
read strobe
chip select strobe
valid
valid
valid
Summary of Contents for 2000
Page 1: ...Rabbit 2000 Microprocessor User s Manual 019 0069 041018 M...
Page 12: ...6 Rabbit 2000 Microprocessor...
Page 46: ...40 Rabbit 2000 Microprocessor...
Page 54: ...48 Rabbit 2000 Microprocessor...
Page 76: ...70 Rabbit 2000 Microprocessor...
Page 96: ...90 Rabbit 2000 Microprocessor...
Page 142: ...136 Rabbit 2000 Microprocessor...
Page 154: ...148 Rabbit 2000 Microprocessor...
Page 170: ...164 Rabbit 2000 Microprocessor...
Page 174: ...168 Rabbit 2000 Microprocessor...
Page 180: ...174 Rabbit 2000 Microprocessor...
Page 202: ...196 Rabbit 2000 Microprocessor...
Page 206: ...200 Rabbit 2000 Microprocessor...
Page 226: ......
Page 230: ...224 Rabbit 2000 Microprocessor...