VRS51C1000-40-PG Ramtron, VRS51C1000-40-PG Datasheet - Page 21

• Manufacturer Part Number: VRS51C1000-40-PG
• Description: Microcontrollers (MCU) 64K+1K 40MHz 5V
• Manufacturer: Ramtron

Specifications of VRS51C1000-40-PG

• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 64 KB
• Data Ram Size: 1 KB
• Interface Type: UART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 36
• Number Of Timers: 3
• Operating Supply Voltage: 4.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Package / Case: PDIP-40
• Minimum Operating Temperature: - 40 C
• Lead Free Status / Rohs Status: Details

Timer 2 Baud Rate Generator Mode
Timer 2 can be used for UART Baud Rate generation.
This Mode is activated when RCLK is set to 1 and/or
TCLK is set to 1. This Mode is described further in the
serial port section.
UART Serial Port
The VRS51C1000’s serial port can operate in full
duplex mode (it can transmit and receive data
simultaneously). This occurs at the same speed if one
timer is assigned as the clock source for both
transmission and reception, and at different speeds if
transmission and reception are each controlled by their
own timer.
The VRS51C1000 serial port includes a double buffer
for the reciever, which allows reception of a byte even
if the previously received one has not been retrieved
from the receive register by the processor. However, if
the first byte still has not been read by the time
reception of the second byte is complete, the byte
present in the receive buffer will be lost.
The SBUF register provides access to the transmit and
receive registers of the serial port. Reading from the
SBUF register will access the receive register, while a
write to the SBUF loads the transmit register.
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F
T2 pin
T2EX pin
IGURE
F
VRS51C1000
OSC
15: T
IMER
EXEN2
÷2
C/T2
2
IN AUTOMATIC
0
1
TR2
COUNTER
TIMER
Timer 1 Overflow
B
AUD
G
ENERATOR
÷2
0
0
0
1
SMOD
M
RCAP2L
TL2
ODE
1
0
TCLK
7
7
0
0
EXF2
1
0
RCLK
RCAP2H
TH2
7
7
÷16
÷16
TX Clock
RX Clock
Timer 2
Interrupt
Request
Serial Port Control Register
The SCON (serial port control) register contains control
and status information, and includes the 9
transmit/receive (TB8/RB8 if required), mode selection
bits and serial port interrupt bits (TI and RI).
T
ABLE
5
4
3
2
1
0
Bit
7
6
SM0
7
30: S
ERIAL
SM2
REN
TB8
RB8
TI
RI
Mnemonic
SM0
SM1
SM1
6
P
ORT
C
SM2
ONTROL
5
Description
Bit to select mode of operation (see table
below)
Bit to select mode of operation (see table
below)
Multiprocessor communication is possible
in Modes 2 and 3.
In Modes 2 or 3 if SM2 is set to 1, RI will
not be activated if the received 9
(RB8) is 0.
In Mode 1, if SM2 = 1 then RI will not be
activated if a valid stop bit was not
received.
Serial Reception Enable Bit
This bit must be set by software and
cleared by software.
1: Serial reception enabled
0: Serial reception disabled
9
This bit must be set by software and
cleared by software.
9
In Mode 1, if SM2 = 0, RB8 is the stop bit
that was received.
In Mode 0, this bit is not used.
This bit must be cleared by software.
Transmission Interrupt flag.
Automatically set to 1 when:
This bit must be cleared by software.
Reception Interrupt flag
Automatically set to 1 when:
This bit must be cleared by software.
N The 8
N Automatically set to 1 when the stop bit
N The 8
N Automatically set to 1 when the stop bit
th
th
R
has been sent in the other modes (see
SM2 exception).
data bit transmitted in Modes 2 and 3
data bit received in Modes 2 and 3.
has been sent in the other modes.
EGISTER
REN
4
th
th
bit has been received in Mode 0.
bit has been sent in Mode 0.
(SCON) – SFR 98
TB8
3
page 21 of 48
RB8
2
H
th
TI
1
data bit for
th
data bit
RI
0