Z8523016VEG Datasheet, PDF (38/118 Pages) Zilog, Inc. – Enhanced Serial Communications Controller

Z80230/Z85230/L
Product Specification
33
bits are decoded to form the register address. This bit is placed in this register to simplify
programming when the current state of the Shift right/Shift Left bit is not known.
A hardware reset forces SHIFT LEFT mode where the address is decoded from 
AD5–AD0. In SHIFT RIGHT mode, the address is decoded from AD4–AD0. The Shift
Right/Shift Left bit is written using a command to make the software writing to WR0 inde-
pendent of the state of the Shift Right/Shift Left bit.
While in the SHIFT LEFT mode, the register address is placed on AD4–AD0 and the
Channel Select bit A/B, is decoded from AD5. In SHIFT RIGHT mode, the register
address is again placed on AD4–AD1 but the Channel Select A/B is decoded from AD0.
Since Z80230 does not contain 16 read registers, the decoding of the read registers is not
complete; this state is listed in Table 4 on page 23 and Table 5 by parentheses around the
register name. These addresses may also be used to access the read registers. The Z80230
contains only one WR2 and WR9; these registers may be written from either channel.
SHIFT LEFT mode is used when Channel A and B are programmed differently. Using
SHIFT LEFT mode allows the software to sequence through the registers of one channel
at a time. The SHIFT RIGHT mode is used when the channels are programmed the same.
By incrementing the address, you can program the same data value into both Channel A
and Channel B registers.
Table 5 lists details of the Z80X30 Register Map in SHIFT LEFT Mode.
Table 5. Z80230 Register Map (Shift Left Mode)
AD5
0
0
0
0
0
0
0
0
0
0
0
0
AD4
0
0
0
0
0
0
0
0
1
1
1
1
AD3
0
0
0
0
1
1
1
1
0
0
0
0
AD2
0
0
1
1
0
0
1
1
0
0
1
1
AD1
0
1
0
1
0
1
0
1
0
1
0
1
Write
WR08
WR1B
WR2
WR3B
WR4B
WR5B
WR6B
WR7B
WR8B
WR9
WR10B
WR11B
80230
80230
80230 WR15 D2=1
WR15 D2=0 WR15 D2=1 WR7’ D6=1
RR0B
RR1B
RR2B
RR3B
RR0B
RR1B
RR2B
RR3B
RR08
RR1B
RR2B
RR3B
(RR0B)
(RR1B)
RR6B
RR7B
(RR0B)
(RR1B)
(RR2B)
(RR3B)
(WR4B)
(WR5B)
RR6B
RR7B
RR8B
(RR13B)
RR10B
(RR15B)
RR8B
(RR13B)
RR10B
(RR15B)
RR8B
(WR3B)
RR10B
(WR10B)
PS005308-0609
Programming