Table of Contents
Advertisement
The meaning of n is shown in table 10.10.
Table 10.10 Relation between n and Clock
n
0
1
2
3
10.3.3
Operation
SCI3 supports serial data communication in both asynchronous mode, where each character
transferred is synchronized separately, and synchronous mode, where transfer is synchronized by
clock pulses.
The choice of asynchronous mode or synchronous mode, and the communication format, is made
in the serial mode register (SMR), as shown in table 10.11. The SCI3 clock source is determined
by bit COM in SMR and bits CKE1 and CKE0 in serial control register 3 (SCR3), as shown in
table 10.12.
Asynchronous Mode:
• Data length: choice of 7 bits or 8 bits
• Options include addition of parity bit, multiprocessor bit, and one or two stop bits
(transmit/receive format and character length are determined by this combination of options).
• Framing error (FER), parity error (PER), overrun error (OER), and line breaks can be detected
when data is received.
• Clock source: Choice of internal clocks or an external clock
When an internal clock is selected: Operates on baud rate generator clock. A clock can be
output with the same frequency as the bit rate.
When an external clock is selected: A clock input with a frequency 16 times the bit rate is
required (internal baud rate generator is not used).
Clock
φ
φ/4
φ/16
φ/64
10. Serial Communication Interface
SMR Setting
CKS1
0
0
1
1
Rev.3.00 Jul. 19, 2007 page 279 of 532
CKS0
0
1
0
1
REJ09B0397-0300
Advertisement
Table of Contents
