UPSD3234A-40U6T STMicroelectronics, UPSD3234A-40U6T Datasheet - Page 68

• Manufacturer Part Number: UPSD3234A-40U6T
• Description: IC MCU 8032 64KB FLASH 80TQFP
• Manufacturer: STMicroelectronics
• Series: µPSDr

Specifications of UPSD3234A-40U6T

• Core Processor: 8032
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, UART/USART, USB
• Peripherals: LVR, POR, PWM, WDT
• Number Of I /o: 46
• Program Memory Size: 288KB (288K x 8)
• Program Memory Type: FLASH
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 4x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP, 80-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

Standard serial interface (UART)
12.2.1
12.2.2
12.2.3
Note:
68/189
Table 44.
Baud rates
The baud rate in Mode 0 is fixed:
The baud rate in Mode 2 depends on the value of Bit SMOD = 0 (which is the value on
reset), the baud rate is 1/64 the oscillator frequency. If SMOD = 1, the baud rate is 1/32 the
oscillator frequency.
In the UPSD323xx devices, the baud rates in Modes 1 and 3 are determined by the Timer 1
overflow rate.
Using Timer 1 to generate baud rates
When Timer 1 is used as the baud rate generator, the baud rates in Modes 1 and 3 are
determined by the Timer 1 overflow rate and the value of SMOD as follows:
The Timer 1 Interrupt should be disabled in this application. The Timer itself can be
configured for either “timer” or “counter” operation, and in any of its 3 running modes. In the
most typical applications, it is configured for “timer” operation, in the Auto-reload mode (high
nibble of TMOD = 0010B). In that case the baud rate is given by the formula:
One can achieve very low baud rates with Timer 1 by leaving the Timer 1 Interrupt enabled,
and configuring the Timer to run as a 16-bit timer (high nibble of TMOD = 0001B), and using
the Timer 1 Interrupt to do a 16-bit software reload.
baud rates and how they can be obtained from Timer 1.
Using Timer/counter 2 to generate baud rates
In the UPSD323xx devices, Timer 2 selected as the baud rate generator by setting TCLK
and/or RCLK (see
The baud rate for transmit and receive can be simultaneously different. Setting RCLK and/or
TCLK puts Timer into its Baud Rate Generator mode.
The RCLK and TCLK Bits in the T2CON register configure UART 1. The RCLK1 and TCLK1
Bits in the PCON register configure UART 2.
The Baud Rate Generator mode is similar to the Auto-reload Mmode, in that a roll over in
TH2 causes the Timer 2 registers to be reloaded with the 16-bit value in registers RCAP2H
and RCAP2L, which are preset by software.
Bit
Mode 0 Baud Rate = f
Mode 2 Baud Rate = (2
Modes 1 and 3 Baud Rate = (2
Modes 1 and 3 Baud Rate = (2
1
0
Description of the SCON bits (continued)
Symbol
RI
TI
Figure 21
Transmit Interrupt Flag. Set by hardware at the end of the 8th bit time in
Mode 0, or at the beginning of the Stop bit in the other modes, in any serial
transmission. Must be cleared by software
Receive Interrupt Flag. Set by hardware at the end of the 8th bit time in
Mode 0, or halfway through the Stop bit in the other modes, in any serial
reception (except for SM2). Must be cleared by software
OSC
SMOD
Timer/ Counter 2 Control Register (T2CON)).
/ 12
UPSD3234A, UPSD3234BV, UPSD3233B, UPSD3233BV
/ 64) x f
SMOD
SMOD
/ 32) x (Timer 1 overflow rate)
/ 32) x (f
OSC
OSC
Figure 21
Function
/ (12 x [256 – (TH1)]))
lists various commonly used