359
Bit 1:
CKE1
Bit 0:
CKE0
Description
*
1
0
0
Asynchronous mode
Internal clock, SCK pin used for input pin (input signal
is ignored) or output pin (output level is undefined)
*
2
(Initial value)
Synchronous mode
Internal clock, SCK pin used for serial clock output
*
2
(Initial value)
0
1
Asynchronous mode
Internal clock, SCK pin used for clock output
*
3
Synchronous mode
Internal clock, SCK pin used for serial clock output
1
0
Asynchronous mode
External clock, SCK pin used for clock input
*
4
Synchronous mode
External clock, SCK pin used for serial clock input
1
1
Asynchronous mode
External clock, SCK pin used for clock input
*
4
Synchronous mode
External clock, SCK pin used for serial clock input
Notes:
*
1 The SCK pin is multiplexed with other functions. Set the pin function controller (PFC) to
select the SCK function and SCK input/output for the SCK pin.
*
2 Initial value
*
3 The output clock frequency is the same as the bit rate.
*
4 The input clock frequency is 16 times the bit rate.
13.2.7
Serial Status Register
The serial status register (SSR) is an 8-bit register containing multiprocessor bit values, and status
flags that indicate the SCI operating status.
The CPU can always read and write to SSR, but cannot write 1 in the status flags (TDRE, RDRF,
ORER, PER, and FER). These flags can be cleared to 0 only if they have first been read (after
being set to 1). Bits 2 (TEND) and 1 (MPB) are read-only bits that cannot be written. SSR is
initialized to H'84 by a reset and in standby mode.
Bit:
7
6
5
4
3
2
1
0
Bit name:
TDRE
RDRF
ORER
FER
PER
TEND
MPB
MPBT
Initial value:
1
0
0
0
0
1
0
0
R/W:
R/(W)
*
R/(W)
*
R/(W)
*
R/(W)
*
R/(W)
*
R
R
R/W
Note:
*
Only 0 can be written, to clear the flag.
•
Bit 7 (Transmit Data Register Empty (TDRE)): TDRE indicates that the SCI has loaded
transmit data from TDR into TSR and new serial transmit data can be written in TDR.
Содержание HD6417032
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Страница 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
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