Texas Instruments TMS320 2833 Series

I2C_Boot
SetCopyWordfunction
pointerto
I2C_CopyWord
EnableSDAAand
SCLApins
Enablepullupson
SDAAandSCLA
EnableI2C-Aclock
Setslaveaddress0x50
I2CprescalerI2CPSC=1
100-kHzbitrateat
24-MHzSYSCLKOUT
(A)
EnableTX/RXFIFOsto
receive2bytes.
PlaceI2Cinmaster
transmittermode
SetEEPROMaddress
pointerto0x0000
NACK
received
?
Yes
ReadKeyValue
No
Valid
KeyValue
(0x08AA)
?
Return
FLASH_ENTRY_POINT
No
ReadI2CPSCvalue
ReadI2CCLKHvalue
Read12CCLKLvalue
Put12c-AinReset
SetI2CPSCvalue
SetI2CCLKHvalue
SetI2CCLKLvalue
BringI2C-AoutofReset
Readanddiscard5
reservedwords
Yes
ReadEntryPoint
address
CallCopyData
Return
EntryPoint
Return
FLASH_ENTRY_POINT
Bootloader Features www.ti.com
208
SPRUI07–March 2020
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Boot ROM
Figure 2-34. Overview of I2C_Boot Function
A During device boot, SYSCLKOUT will be the device input frequency divided by two.
The nonacknowledgment bit is checked only during the first message sent to initialize the EEPROM base
address. This is to make sure that an EEPROM is present at address 0x50 before continuing. If an
EEPROM is not present, code will jump to the flash entry point. The nonacknowledgment bit is not
checked during the address phase of the data read messages (I2C_Get Word). If a non acknowledgment
is received during the data read messages, the I2C bus will hang. Table 2-14 shows the 8-bit data stream
used by the I2C.