AT89C5132-ROTIL Atmel, AT89C5132-ROTIL Datasheet - Page 108

• Manufacturer Part Number: AT89C5132-ROTIL
• Description: IC 8051 MCU FLASH 64K USB 80TQFP
• Manufacturer: Atmel
• Series: AT89C513xr

Specifications of AT89C5132-ROTIL

• Core Processor: C52X2
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: IDE/ATAPI, I²C, MMC, PCM, SPI, UART/USART, USB
• Peripherals: I²S, POR, WDT
• Number Of I /o: 44
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 2x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 80-TQFP, 80-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

18.2.2
18.3
108
Synchronous Mode (Mode 0)
AT89C5132
Internal Baud Rate Generator
Figure 18-1. Timer 1 Baud Rate Generator Block Diagram
When using the Internal Baud Rate Generator, the Baud Rate is derived from the overflow of the
timer. As shown in Figure 18-2, the Internal Baud Rate Generator is an 8-bit auto-reload timer
feed by the peripheral clock or by the peripheral clock divided by 6 depending on the SPD bit in
BDRCON register (see Table 95). The Internal Baud Rate Generator is enabled by setting BBR
bit in BDRCON register. SMOD1 bit in PCON register allows doubling of the generated baud
rate.
Figure 18-2. Internal Baud Rate Generator Block Diagram
Mode 0 is a half-duplex, synchronous mode, which is commonly used to expand the I/0 capabil-
ities of a device with shift registers. The transmit data (TXD) pin outputs a set of eight clock
pulses while the receive data (RXD) pin transmits or receives a byte of data. The 8-bit data are
transmitted and received least-significant bit (LSB) first. Shifts occur at a fixed Baud Rate (see
Section "Baud Rate Selection (Mode 0)", page 110). Figure 18-3 shows the serial port block dia-
gram in Mode 0.
CLOCK
CLOCK
INT1
PER
PER
T1
GATE1
TMOD.7
TCON.6
TR1
÷ 6
÷ 6
BDRCON.1
TMOD.6
SPD
C/T1#
0
1
0
1
BDRCON.4
BRR
(8 bits)
(8 bits)
(8 bits)
(8 bits)
BRG
BRL
TH1
TL1
To serial
Port (M0)
Overflow
Overflow
CLOCK
IBRG0
÷ 2
÷ 2
SMOD1
SMOD1
PCON.7
CLOCK
PCON.7
T1
0
1
0
1
CLOCK
IBRG
4173E–USB–09/07
To serial
Port
To serial
Port