Z85233 Datasheet, PDF (17/317 Pages) Zilog, Inc. – The Zilog SCC Serial Communication Controller

AD1
AD3
AD5
AD7
/INT
IEO
IEI
/INTACK
VCC
/W//REQA
/SYNCA
/RTxCA
RxDA
/TRxCA
TxDA
/DTR//REQA
/RTSA
/CTSA
/DCDA
PCLK
1
40
2
39
3
38
4
37
5
36
6
35
7
34
8
33
9
32
10
31
Z80X30
11
30
12
29
13
28
14
27
15
26
16
25
17
24
18
23
19
22
20
21
AD0
AD2
AD4
AD6
/DS
/AS
R//W
/CS0
CS1
GND
/W//REQB
/SYNCB
/RTxCB
RxDB
/TRxCB
TxDB
/DTR//REQB
RTSB
/CTSB
/DCDB
Figure 1-6. Z80X30 DIP Pin Assignments
SCC™/ESCC™ User’s Manual
General Description
1
Figure 1-7. Z80X30 PLCC Pin Assignments
1.4.1 Pins Common to both Z85X30 and
Z80X30
/CTSA, /CTSB. Clear To Send (inputs, active Low). These
pins function as transmitter enables if they are pro-
grammed for Auto Enable (WR3, D5=1). A Low on the in-
puts enables the respective transmitters. If not pro-
grammed as Auto Enable, they may be used as general-
purpose inputs. Both inputs are Schmitt-trigger buffered to
accommodate slow rise-time inputs. The SCC detects
pulses on these inputs and can interrupt the CPU on both
logic level transitions.
/DCDA, /DCDB. Data Carrier Detect (inputs, active Low).
These pins function as receiver enables if they are pro-
grammed for Auto Enable (WR3, D5=1); otherwise, they
are used as general-purpose input pins. Both pins are
Schmitt-trigger buffered to accommodate slow rise time
signals. The SCC detects pulses on these pins and can in-
terrupt the CPU on both logic level transitions.
/RTSA, /RTSB. Request To Send (outputs, active Low).
The /RTS pins can be used as general-purpose outputs or
with the Auto Enable feature. When used with Auto Enable
ON (WR3, D5=1) in asynchronous mode, the /RTS pin
goes High after the transmitter is empty. When Auto En-
able is OFF, the /RTS pins are used as general-purpose
outputs, and, they strictly follow the inverse state of WR5,
bit D1.
ESCC and 85C30:
In SDLC mode, the /RTS pins can be programmed to
be deasserted when the closing flag of the message
clears the TxD pin, if WR7' D2 is set.
/SYNCA, /SYNCB. Synchronization (inputs or outputs, ac-
tive Low). These pins can act either as inputs, outputs, or
part of the crystal oscillator circuit. In the Asynchronous
Receive mode (crystal oscillator option not selected),
these pins are inputs similar to CTS and DCD. In this
mode, transitions on these lines affect the state of the Syn-
chronous/Hunt status bits in Read Register 0 but have no
other function.
In External Synchronization mode, with the crystal oscilla-
tor not selected, these lines also act as inputs. In this
mode, /SYNC is driven Low to receive clock cycles after
the last bit in the synchronous character is received. Char-
acter assembly begins on the rising edge of the receive
clock immediately preceding the activation of SYNC.
In the Internal Synchronization mode (Monosync and Bi-
sync) with the crystal oscillator not selected, these pins
act as outputs and are active only during the part of the
UM010901-0601
1-7