msm9405 Oki Semiconductor, msm9405 Datasheet - Page 28

• Manufacturer Part Number: msm9405
• Description: Irda Communication Controller
• Manufacturer: Oki Semiconductor

¡ Semiconductor
MSM9405
TFL : (Transmitter Frame Length Register
TCC : Transmitter Current-Count Register (Address = 9, Ah)
The TFL (Transmitter Frame Length) and TCC (Transmitter Current-Count Register) are used
to specify the length of the frame to be transferred for sending. The TFL and TCC shares the
same address. Bits 0 to 7 of address 9h and bits 0 to 3 of address Ah (totally 12 bits) are used.
Bit 0 of address 9h is the LSB.
When the TFL/TCC value is read, the CTEST setting is reflected. If CTEST = "0", the TCC
contents can be read. If CTEST = "1", the TFL contents can be read. When the TFL/TCC is
written, the TFL value is rewritten. The TCC cannot be written.
To use the TFL/TCC, write "1" to TCC_EN, and set the frame length in the TFL. The frame length
to be set does not include the CE, FCS, BOF, and EOF. When "1" is written to TX_EN, the TFL
value that has been set as the frame length is loaded to the TCC. When sending is started, the
TCC value is decremented by 1 each time 1 byte is sent. When the TCC value becomes "0", the
end of frame is assumed and the frame is automatically added with the CRC and EOF and sent.
After one frame is sent, the TFL value is loaded again into the TCC when the BOF of the second
frame is sent.
The TFL/TCC initial value is set to 800h.
MDS : Maximum Data Size Register
RST : Receiver Frame Length Stack Register (Address = B, Ch)
The MDS (Maximum Data Size Register) is used to set the maximum data size. The RST
(Receiver Frame Length Stack Register) is used to stack the received frame length. The MDS and
RST share the same address. Bits 0 to 7 of address Bh and bits 0 to 3 of address Ch (totally 12
bits) are used. Bit 0 of address Bh is the LSB.
When the MDS/RST value is read, the CTEST setting is reflected. If CTEST = "0", the RST
contents can be read. If CTEST = "1", the MDS contents can be read. When the MDS/RST is
written, the MDS value is rewritten. The RST cannot be written.
To use the MDS, set the maximum data size in the MDS in advance. The frame length to be set
does not include the CE, FCS, BOF, and EOF in the Extended-SIR, MIR, and FIR modes.
(However, it does include them in the SIR mode.) When receiving is started, the internal counter
value is incremented by 1 each time one byte is received. If the internal counter value exceeds
the MDS value during receiving, MLE occurs. The MDS initial value is set to 800h.
When a frame is fully received and all the data in the received frame is taken out of the FIFO,
the received frame length counted by the internal counter is stacked in the RST. This value is
stored untill the next frame is fully received. The value stacked in the RST is maintained even
if MSM9405 sending/receiving is switched. The RST initial value is set to 0h.
TEST : Test Register (Address = Fh)
This register is used for testing.
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