tda9950 NXP Semiconductors, tda9950 Datasheet - Page 11

• Manufacturer Part Number: tda9950
• Description: Tda9950 Cec/i?c-bus Translator
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDA9950_1
Product data sheet
Fig 4. Host reads TDA9950 Status Register - after setting address pointer
Fig 5. Host reads TDA9950 Status Register - without setting address pointer (was at 0)
A = acknowledge (SDA = LOW)
S = START condition
P = STOP condition
A = acknowledge (SDA = LOW)
S = START condition
P = STOP condition
S
from master to slave
8.6 Example communication sequences
SLAVE ADDRESS
When writing, the first byte after the slave address will contain the Address Pointer
Register value. Subsequent bytes are written to the register addressed by the Address
Pointer Register.
If the host wishes to write to two or more discontiguous registers, two separate write
sequences must be used with a STOP/START or repeated START condition between
them. Contiguous ranges of registers can be written in one communication sequence
between a START and STOP condition. Messages in the CEC Data Registers must be
written and read as contiguous ranges of registers.
When reading, values are read starting at the register currently addressed by the Address
Pointer Register. The pointer auto-increments after each read. If the host should read past
register 19h, or read more bytes than indicated by the FrameByteCount in register CDR[0]
(address 07h), the value FFh will be returned.
When the address pointer is 00h, it does not auto-increment. This allows repetitive polling
of the TDA9950 Status Register without the need to reset the Address Pointer Register.
If the address pointer needs to be set before a read takes place, the host must first write to
the Address Pointer Register and then, after a repeated start condition (or a STOP/START
sequence), commence reading as many data bytes as it requires.
'0' (write)
W
S
from master to slave
A
write address pointer
SLAVE ADDRESS
from slave to master
00000000
Rev. 01 — 16 November 2007
Sr = repeated START condition
A
'1' (read)
Sr
R
SLAVE ADDRESS
A
from slave to master
read status
<CSR>
001aag926
A
'1' (read)
P
R
A
read status
<CSR>
CEC/I
TDA9950
© NXP B.V. 2007. All rights reserved.
2
001aag925
C-bus translator
A
P
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