S912XEP768J5MAGR Freescale Semiconductor, S912XEP768J5MAGR Datasheet - Page 735

• Manufacturer Part Number: S912XEP768J5MAGR
• Description: 16-bit Microcontrollers - MCU 16-bit 768K Flash
• Manufacturer: Freescale Semiconductor

Specifications of S912XEP768J5MAGR

• Rohs: yes
• Core: HCS12X
• Processor Series: MC9S12
• Data Bus Width: 16 bit
• Maximum Clock Frequency: 50 MHz
• Program Memory Size: 768 KB
• Data Ram Size: 48 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3.3 V to 5 V
• Operating Temperature Range: - 40 C to + 125 C
• Package / Case: LQFP-144
• Mounting Style: SMD/SMT

20.3.2.7
The SCISR1 and SCISR2 registers provides inputs to the MCU for generation of SCI interrupts. Also,
these registers can be polled by the MCU to check the status of these bits. The flag-clearing procedures
require that the status register be read followed by a read or write to the SCI data register.It is permissible
to execute other instructions between the two steps as long as it does not compromise the handling of I/O,
but the order of operations is important for flag clearing.
Read: Anytime
Write: Has no meaning or effect
Freescale Semiconductor
Module Base + 0x0004
Reset
RDRF
TDRE
Field
IDLE
TC
7
6
5
4
W
R
TDRE
Transmit Data Register Empty Flag — TDRE is set when the transmit shift register receives a byte from the
SCI data register. When TDRE is 1, the transmit data register (SCIDRH/L) is empty and can receive a new value
to transmit.Clear TDRE by reading SCI status register 1 (SCISR1), with TDRE set and then writing to SCI data
register low (SCIDRL).
0 No byte transferred to transmit shift register
1 Byte transferred to transmit shift register; transmit data register empty
Transmit Complete Flag — TC is set low when there is a transmission in progress or when a preamble or break
character is loaded. TC is set high when the TDRE flag is set and no data, preamble, or break character is being
transmitted.When TC is set, the TXD pin becomes idle (logic 1). Clear TC by reading SCI status register 1
(SCISR1) with TC set and then writing to SCI data register low (SCIDRL). TC is cleared automatically when data,
preamble, or break is queued and ready to be sent. TC is cleared in the event of a simultaneous set and clear of
the TC flag (transmission not complete).
0 Transmission in progress
1 No transmission in progress
Receive Data Register Full Flag — RDRF is set when the data in the receive shift register transfers to the SCI
data register. Clear RDRF by reading SCI status register 1 (SCISR1) with RDRF set and then reading SCI data
register low (SCIDRL).
0 Data not available in SCI data register
1 Received data available in SCI data register
Idle Line Flag — IDLE is set when 10 consecutive logic 1s (if M = 0) or 11 consecutive logic 1s (if M =1) appear
on the receiver input. Once the IDLE flag is cleared, a valid frame must again set the RDRF flag before an idle
condition can set the IDLE flag.Clear IDLE by reading SCI status register 1 (SCISR1) with IDLE set and then
reading SCI data register low (SCIDRL).
0 Receiver input is either active now or has never become active since the IDLE flag was last cleared
1 Receiver input has become idle
Note: When the receiver wakeup bit (RWU) is set, an idle line condition does not set the IDLE flag.
SCI Status Register 1 (SCISR1)
1
7
= Unimplemented or Reserved
TC
1
6
Figure 20-10. SCI Status Register 1 (SCISR1)
MC9S12XE-Family Reference Manual Rev. 1.25
Table 20-11. SCISR1 Field Descriptions
RDRF
0
5
IDLE
0
4
Description
OR
Chapter 20 Serial Communication Interface (S12SCIV5)
0
3
NF
0
2
FE
0
1
PF
0
0
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