ST72C334J4T6 STMicroelectronics, ST72C334J4T6 Datasheet - Page 91

• Manufacturer Part Number: ST72C334J4T6
• Description: MCU 8BIT FLASH SPI SCI 44TQFP
• Manufacturer: STMicroelectronics
• Series: ST7r

Specifications of ST72C334J4T6

• Core Processor: ST7
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SCI, SPI
• Peripherals: LVD, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 3.2 V ~ 5.5 V
• Data Converters: A/D 6x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Processor Series: ST72C3x
• Core: ST7
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 4 bit
• Operating Supply Voltage: 3.2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Development Tools By Supplier: ST7C334-INDART, ST7MDT2-EPB2/US
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-4838

SERIAL COMMUNICATIONS INTERFACE (Cont’d)
14.5.5.4 Conventional Baud Rate Generation
The baud rate for the receiver and transmitter (Rx
and Tx) are set independently and calculated as
follows:
with:
PR = 1, 3, 4 or 13 (see SCP0 & SCP1 bits)
TR = 1, 2, 4, 8, 16, 32, 64,128
(see SCT0, SCT1 & SCT2 bits)
RR = 1, 2, 4, 8, 16, 32, 64,128
(see SCR0,SCR1 & SCR2 bits)
All this bits are in the BRR register.
Example: If f
PR=13 and TR=RR=1, the transmit and receive
baud rates are 19200 baud.
Caution: The baud rate register (SCIBRR) MUST
NOT be written to (changed or refreshed) while the
transmitter or the receiver is enabled.
14.5.5.5 Extended Baud Rate Generation
The extended prescaler option gives a very fine
tuning on the baud rate, using a 255 value prescal-
er, whereas the conventional Baud Rate Genera-
tor retains industry standard software compatibili-
ty.
The extended baud rate generator block diagram
is described in the Figure 3..
The output clock rate sent to the transmitter or to
the receiver will be the output from the 16 divider
divided by a factor ranging from 1 to 255 set in the
ERPR or the ETPR register.
Note: the extended prescaler is activated by set-
ting the ETPR or ERPR register to a value other
Tx =
(32
f
CPU
*
PR)
CPU
*
TR
is 8 MHz (normal mode) and if
Rx =
(32
f
CPU
*
PR)
*
RR
than zero. The baud rates are calculated as fol-
lows:
with:
ETPR = 1,..,255 (see ETPR register)
ERPR = 1,.. 255 (see ERPR register)
14.5.5.6 Receiver Muting and Wake-up Feature
In multiprocessor configurations it is often desira-
ble that only the intended message recipient
should actively receive the full message contents,
thus reducing redundant SCI service overhead for
all non addressed receivers.
The non addressed devices may be placed in
sleep mode by means of the muting function.
Setting the RWU bit by software puts the SCI in
sleep mode:
All the reception status bits can not be set.
All the receive interrupt are inhibited.
A muted receiver may be awakened by one of the
following two ways:
– by Idle Line detection if the WAKE bit is reset,
– by Address Mark detection if the WAKE bit is set.
Receiver wakes-up by Idle Line detection when
the Receive line has recognised an Idle Frame.
Then the RWU bit is reset by hardware but the
IDLE bit is not set.
Receiver wakes-up by Address Mark detection
when it received a “1” as the most significant bit of
a word, thus indicating that the message is an ad-
dress. The reception of this particular word wakes
up the receiver, resets the RWU bit and sets the
RDRF bit, which allows the receiver to receive this
word normally and to use it as an address word.
Tx =
ST72334J/N, ST72314J/N, ST72124J
16
f
CPU
*
ETPR
Rx =
16
f
CPU
*
ERPR
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