em78p5830aa ELAN Microelectronics Corp, em78p5830aa Datasheet - Page 13

• Manufacturer Part Number: em78p5830aa
• Description: 8-bit Micro-controller 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

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* This specification is subject to be changed without notice.
SDO/P75
SDI/P74
SPIC reg. : SPI control register
SDO: Serial data out
SDI: Serial data in
SCK: Serial clock
RBF : Set by buffer full detector, and reset in software.
RBFI : Interrupt flag. Set by buffer full detector, and reset in software.
Buffer Full Detector : Sets to 1, while an 8-bit shifting is complete.
SE : Loads the data in SPIW register, and begin to shift
SPIE : SPI control register
SPIS reg. : Shifting byte out and in.
SPIR reg. : Read buffer.
SPIW reg. : Write buffer.
SBR2 ~ SBR0: Programming the clock frequency/rates and sources.
Clock select : Selecting either the internal instruction clock or the external 16.338KHz clock as the shifting clock.
Edge Select : Selecting the appropriate clock edges by programming the SCES bit
The MSB will be shifted first. Both the SPIS register and the SPIW register are loaded at the same time. Once
data being written to, SPIS starts transmission / reception. The received data will be moved to the SPIR
register, as the shifting of the 8-bit data is complete. The RBF (Read Buffer Full ) flag and the RBFI(Read
Buffer Full Interrupt) flag are set.
The buffer will be updated as the 8-bit shifting is complete. The data must be read before the next reception is
finished. The RBF flag is cleared as the SPIR register read.
The buffer will deny any write until the 8-bit shifting is complete. The SE bit will be kept in 1 if the
communication is still under going. This flag must be cleared as the shifting is finished. Users can determine if
the next write attempt is available.
MUX
MUX
SPIE
SPIE
PORT61
PORT62
SDI
SDO
Buffer Full Detector
T
RBF
sco
16.38kHz
set to 1
0
RBFI
4, 8, 16, 32, 64, 128
SBR0 ~SBR2
Prescaler
Read
R5
SPIR reg.
3
bit 0
SBR2~SBR0
Fig.5 SPI structure
3
SPIS reg.
SPIWC
11
Clock Select
Select
2
Edge
SCK
Write
R5
shift right
SPIW reg.
Select
Edge
bit 7
Noise
Filter
SPIC reg. (R4 page1)
PORT60
SCK
8-bit Micro-controller
MUX
SPIE
12/1/2004 V1.6
EM785830AA
SCK/P76