S912XET512J3VALR Freescale Semiconductor, S912XET512J3VALR Datasheet - Page 742

Manufacturer Part Number

S912XET512J3VALR

16-bit Microcontrollers - MCU 16 BIT,512K FLASH

Manufacturer

Freescale Semiconductor

Processor Series

Data Bus Width

Maximum Clock Frequency

Program Memory Size

Data Ram Size

Operating Supply Voltage

3.13 V to 5.5 V

Operating Temperature Range

- 40 C to + 105 C

Package / Case

Mounting Style

Manufacturer

BOSTOCK HK LIMITED

Part Number:

S912XET512J3VALR

Manufacturer:

Freescale Semiconductor

Chapter 20 Serial Communication Interface (S12SCIV5)

A 13-bit modulus counter in the baud rate generator derives the baud rate for both the receiver and the

transmitter. The value from 0 to 8191 written to the SBR12:SBR0 bits determines the bus clock divisor.

The SBR bits are in the SCI baud rate registers (SCIBDH and SCIBDL). The baud rate clock is

synchronized with the bus clock and drives the receiver. The baud rate clock divided by 16 drives the

transmitter. The receiver has an acquisition rate of 16 samples per bit time.

Baud rate generation is subject to one source of error:

When IREN = 0 then,

Integer division of the bus clock may not give the exact target frequency.

SCI baud rate = SCI bus clock / (16 * SCIBR[12:0])

Baud Rate Generation

lists some examples of achieving target baud rates with a bus clock frequency of 25 MHz.

Table 20-16. Baud Rates (Example: Bus Clock = 25 MHz)

1. The address bit identiﬁes the frame as an address

character. See

MC9S12XE-Family Reference Manual Rev. 1.25

Section 20.4.6.6, “Receiver

Freescale Semiconductor