Z8F042AHH020EG Zilog, Z8F042AHH020EG Datasheet - Page 187

• Manufacturer Part Number: Z8F042AHH020EG
• Description: IC ENCORE XP MCU FLASH 4K 20SSOP
• Manufacturer: Zilog
• Series: Encore!® XP®r

Specifications of Z8F042AHH020EG

• Core Processor: Z8
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: IrDA, UART/USART
• Peripherals: Brown-out Detect/Reset, LED, LVD, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 17
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 7x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 269-4156; Z8F042AHH020EG

PS022517-0508
OCD Auto-Baud Detector/Generator
OCD Serial Errors
To run over a range of baud rates (bits per second) with various system clock frequencies,
the OCD contains an Auto-Baud Detector/Generator. After a reset, the OCD is idle until it
receives data. The OCD requires that the first character sent from the host is the character
80H
The Auto-Baud Detector measures this period and sets the OCD Baud Rate Generator
accordingly.
The Auto-Baud Detector/Generator is clocked by the system clock. The minimum baud
rate is the system clock frequency divided by 512. For optimal operation, the maximum
recommended baud rate is the system clock frequency divided by 8. The theoretical
maximum baud rate is the system clock frequency divided by 4. This theoretical maxi-
mum is possible for low noise designs with clean signals.
recommended maximum baud rates for sample crystal frequencies.
Table 92. OCD Baud-Rate Limits
If the OCD receives a Serial Break (nine or more continuous bits Low) the Auto-Baud
Detector/Generator resets. The Auto-Baud Detector/Generator can then be reconfigured
by sending
The OCD can detect any of the following error conditions on the
•
•
•
When the OCD detects one of these errors, it aborts any command currently in progress,
transmits a Serial Break 4096 System Clock cycles long back to the host, and resets the
Auto-Baud Detector/Generator. A Framing Error or Transmit Collision can be caused by
the host sending a Serial Break to the OCD. Because of the open-drain nature of the inter-
face, returning a Serial Break break back to the host only extends the length of the Serial
Break if the host releases the Serial Break early.
System Clock
Frequency (MHz)
0.032768 (32 kHz)
. The character
Serial Break (a minimum of nine continuous bits Low)
Framing Error (received STOP bit is Low)
Transmit Collision (OCD and host simultaneous transmission detected by the OCD)
20.0
1.0
80H
.
80H
has eight continuous bits Low (one Start bit plus 7 data bits).
Recommended Maximum Baud
Rate (kbps)
125.0
4.096
2500
Z8 Encore! XP
Table 92
Product Specification
Minimum Baud Rate
(Kbps)
DBG
lists minimum and
pin:
®
On-Chip Debugger
0.064
F0822 Series
39.1
1.96
174