Z8F042AHJ020SC00TR Zilog, Z8F042AHJ020SC00TR Datasheet - Page 116

• Manufacturer Part Number: Z8F042AHJ020SC00TR
• Description: IC ENCORE XP MCU FLASH 4K 28SSOP
• Manufacturer: Zilog
• Series: Encore!® XP®r

Specifications of Z8F042AHJ020SC00TR

• 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: 23
• 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 8x10b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: Z8F042AHJ020SC00T

PS022825-0908
DE
1
0
1
0
Idle State
Figure 14. UART Driver Enable Signal Timing (shown with 1 Stop Bit and Parity)
of Line
UART Interrupts
Driver Enable is an active High signal that envelopes the entire transmitted data frame
including parity and Stop bits as displayed in
when a byte is written to the UART Transmit Data register. The Driver Enable signal
asserts at least one UART bit period and no greater than two UART bit periods before the
Start bit is transmitted. This allows a setup time to enable the transceiver. The Driver
Enable signal deasserts one system clock period after the final Stop bit is transmitted. This
one system clock delay allows both time for data to clear the transceiver before disabling
it, as well as the ability to determine if another character follows the current character. In
the event of back to back characters (new data must be written to the Transmit Data Regis-
ter before the previous character is completely transmitted) the DE signal is not deasserted
between characters. The DEPOL bit in the UART Control Register 1 sets the polarity of
the Driver Enable signal.
The Driver Enable to Start bit setup time is calculated as follows:
The UART features separate interrupts for the transmitter and the receiver. In addition,
when the UART primary functionality is disabled, the Baud Rate Generator can also
function as a basic timer with interrupt capability.
Transmitter Interrupts
The transmitter generates a single interrupt when the Transmit Data Register Empty bit
(TDRE) is set to 1. This indicates that the transmitter is ready to accept new data for trans-
mission. The TDRE interrupt occurs after the Transmit shift register has shifted the first
bit of data out. The Transmit Data register can now be written with the next character to
Start
⎛
⎝
---------------------------------------- -
Baud Rate (Hz)
Bit0
lsb
1
Bit1
⎞
⎠
≤
Bit2
DE to Start Bit Setup Time (s)
Bit3
Data Field
Bit4
Bit5
Figure
Universal Asynchronous Receiver/Transmitter
Bit6
14. The Driver Enable signal asserts
Z8 Encore! XP
≤
⎛
⎝
---------------------------------------- -
Baud Rate (Hz)
msb
Bit7
Product Specification
2
Parity
®
Stop Bit
F082A Series
⎞
⎠
1
105