Z85C3008VSG Zilog, Z85C3008VSG Datasheet - Page 60

• Manufacturer Part Number: Z85C3008VSG
• Description: IC 8MHZ Z8500 CMOS SCC 44-PLCC
• Manufacturer: Zilog
• Series: SCCr

Specifications of Z85C3008VSG

• Processor Type: Z80
• Features: Error Detection and Multiprotocol Support
• Speed: 8MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 44-LCC (J-Lead)
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Cpu Speed: 8MHz
• Digital Ic Case Style: LCC
• No. Of Pins: 44
• Supply Voltage Range: 5V
• Operating Temperature Range: 0°C To +70°C
• Svhc: No SVHC (18-Jun-2010)
• Base Number: 85
• Rohs Compliant: Yes
• Clock Frequency: 8MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 269-3932; Z85C3008VSG

UM010901-0601
2.6 TEST FUNCTIONS
The SCC contains two other features useful for diagnostic
purposes, controlled by bits in WR14. They are Local
Loopback and Auto Echo.
2.6.1 Local Loopback
Local Loopback is selected when WR14 bit D4 is set to 1.
In this mode, the output of the transmitter is internally con-
nected to the input of the receiver. At the same time, the
TxD pin remains connected to the transmitter. In this
mode, the /DCD pin is ignored as a receive enable and the
/CTS pin is ignored as a transmitter enable even if the Auto
Enable mode has been selected. Note that the DPLL input
is connected to the RxD pin, not to the input of the receiver.
This precludes the use of the DPLL in Local Loopback. Lo-
cal Loopback is shown schematically in Figure 2-35.
/DCD
RxD
/CTS
TxD
NC
Figure 2-35. Local Loopback
Local Loop Back
Rx Enable
Tx Enable
Transmitter
Receiver
Receiver
2.6.2 Auto Echo
Auto Echo is selected when bit D3 of WR14 is set to 1. In
this mode, the TxD pin is connected directly to the RxD pin,
and the receiver input is connected to the RxD pin. In this
mode, the /CTS pin is ignored as a transmitter enable and
the output of the transmitter does not connect to anything.
If both the Local Loopback and Auto Echo bits are set to 1,
the Auto Echo mode is selected, but both the /CTS pin and
/DCD pin are ignored as auto enables. This should not be
considered a normal operating mode (Figure 2-36).
/DCD
/CTS
RxD
TxD
Figure 2-36. Auto Echo
Auto Echo
SCC™/ESCC™ User’s Manual
Interfacing the SCC/ESCC
NC
Rx Enable
Tx Enable
Transmitter
Receiver
2-41
2