PNX1300 Datasheet, PDF (209/548 Pages) NXP Semiconductors – Media Processors

Philips Semiconductors
System Boot
13.5 EEPROM ACCESS PROTOCOLS
Figure 13-3 shows the SDA (serial data) line protocols
for three types of read accesses supported by I²C serial
EEPROMs. A read from the address currently latched in-
side the EEPROM can be for either a single byte or for
an arbitrary series of sequential bytes. The master
makes the choice by setting the ACK bit after a byte has
been transferred.
A random-access read is accomplished by performing a
dummy write, which overwrites the latched address
stored inside the EEPROM. Once the internal address
latch is set to the desired value, one of the other two read
protocols can be used to read one or more bytes.
The boot logic inside PNX1300 uses a single random
read transaction to location 0 of device address 1010000
followed by a sequential read extension to read all re-
quired EEPROM bytes in a single pass.
Device Address
N
S
O
T
R
S
A
EA
AT
R
APPAC
CO
T 1 0 1 0 0 0 0 DK
KP
SDA Line Protocol:
Current-Address Read
DDDDDDDD
76543210
Data n
Dummy Write
SDA Line Protocol:
Random Read
SDA Line Protocol:
Sequential Read
Device Address
Device Address
S
W
S
T
R
T
R
A
D P P I A WWWWWWWW A A
EA
R
AAA TCAAAAAAAACR
APPAC
T 1 0 1 0 0 0 0 EK 7 6 5 4 3 2 1 0 K T 1 0 1 0 0 1 0 DK
N
O
S
AT
CO
KP
DDDDDDDD
76543210
Device Address
N
S
O
T
R
S
A
EA
A
A
A
AT
R
APPAC
C
C
C
CO
T 1 0 1 0 0 0 0 DK
K
K
K
KP
DDDDDDDD DDDDDDDD DDDDDDDD DDDDDDDD
76543210 76543210 76543210 76543210
Data n
Data n+1
Data n+2
Data n+3
Figure 13-3. Protocols supported by the boot block for reading the EEPROM
PRELIMINARY SPECIFICATION
13-9