MC812A4CPVE8 Freescale Semiconductor, MC812A4CPVE8 Datasheet - Page 167

• Manufacturer Part Number: MC812A4CPVE8
• Description: IC MCU 16BIT EEPROM 4K 112-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC12r

Specifications of MC812A4CPVE8

• Core Processor: CPU12
• Core Size: 16-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: POR, WDT
• Number Of I /o: 83
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: EEPROM
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 112-LQFP
• Processor Series: HC812A
• Core: HC12
• Data Bus Width: 16 bit
• Data Ram Size: 1 KB
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 91
• Number Of Timers: 8
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 8 Channel
• Controller Family/series: 68HC12
• No. Of I/o's: 91
• Eeprom Memory Size: 4KB
• Ram Memory Size: 1KB
• Cpu Speed: 8MHz
• No. Of Timers: 1
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

Enable single-wire operation by setting the LOOPS bit and the receiver source bit, RSRC, in SCI control
register 1 (SCCR1). Setting the LOOPS bit disables the path from the RXD pin to the receiver. Setting the
RSRC bit connects the receiver input to the output of the TXD pin driver. Both the transmitter and receiver
must be enabled (TE = 1 and RE = 1).
The wired-OR mode select bit, WOMS, configures the TXD pin for full CMOS drive or for open-drain drive.
WOMS controls the TXD pin in both normal operation and in single-wire operation. When WOMS is set,
the data direction bit for the TXD pin does not have to be cleared for TXD to receive data.
14.5.6 Loop Operation
In loop operation, the transmitter output goes to the receiver input. The RXD pin is disconnected from the
SCI and is available as a general-purpose I/O pin.
Setting the data direction bit for the TXD pin connects the transmitter output to the TXD pin. Clearing the
data direction bit disconnects the transmitter output from the TXD pin.
Enable loop operation by setting the LOOPS bit and clearing the RSRC bit in SCI control register 1
(SCCR1). Setting the LOOPS bit disables the path from the RXD pin to the receiver. Clearing the RSRC
bit connects the transmitter output to the receiver input. Both the transmitter and receiver must be enabled
(TE = 1 and RE = 1).
The wired-OR mode select bit, WOMS, configures the TXD pin for full CMOS drive or for open-drain drive.
WOMS controls the TXD pin in both normal operation and in loop operation.
Freescale Semiconductor
DDRS BIT = 1
DDRS BIT = 0
Figure 14-16. Loop Operation (LOOP = 1 and RSRC = 0)
TRANSMITTER
TRANSMITTER
RECEIVER
RECEIVER
MC68HC812A4 Data Sheet, Rev. 7
H
WOMS
WOMS
TXD
RXD
TXD
RXD
GENERAL-
PURPOSE I/O
GENERAL-
PURPOSE I/O
Functional Description
167