tmp19a44fda TOSHIBA Semiconductor CORPORATION, tmp19a44fda Datasheet - Page 453

• Manufacturer Part Number: tmp19a44fda
• Description: 32bit Tx System Risc
• Manufacturer: TOSHIBA Semiconductor CORPORATION

Serial Bus Interface (SBI)
16.7.1
SCK pin output
SO pin output
Write the
transmit data
Internal clocks
External clock (<SCK2:0> = "111")
Clock source
Internal or external clocks can be selected by programming SBICR1 <SCK2:0>.
In the internal clock mode, one of the seven frequencies can be selected as a serial clock, which is
output to the outside through the SCK pin. At the beginning of a transfer, the SCK pin output
becomes the "H" level.
If the program cannot keep up with this serial clock rate in writing the transmit data or reading the
received data, the SBI automatically enters a wait period. During this period, the serial clock is
stopped automatically and the next shift operation is suspended until the processing is completed.
The SBI uses an external clock supplied from the outside to the SCK pin as a serial clock. For
proper shift operations, the serial clock at the "H" and "L" levels must have the pulse widths as
shown below.
Fig. 16.16 9 Maximum Transfer Frequency of External Clock Input
Serial Clock
SCK pin
a
a
1
0
t
SCKL
a
, t
2
1
SCKH
TMP19A44 (rev1.3) 16-29
Fig. 16.15 Automatic Wait
a
t
2
SCK
> 8/fsys
3
a
L
5
t
SCK
a
7
H
6
a
Automatic wait
8
7
b
b
1
0
b
1
2
c
b
4
b
6
5
b
7
6
TMP19A44
b
8
7
c
1
0
c
2
1
2010-04-01
c
3
2