Texas Instruments TMS320 2833 Series User Manual

Parallel_Boot
No
Yes
Initialize GP I/O MUX
and Dir registers
GPIO[15:0] = input
GPIO27 = input
GPIO26=output
Read KeyValue to
determine DataSize
Valid
KeyValue
(0x08AA or
0x10AA)
?
reserved words
Read and discard 8
Read EntryPoint
address
CopyData
Call
Return
EntryPoint
Return
FLASH_ENTRY_POINT
Enable pullups on
GPIO[15:0], GPIO26,
and GPIO27
and assign appropriate
GetWordData function
Host control
GPIO27
DSP control
GPIO26
1
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SPRUI07–March 2020
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Boot ROM
The 28x device first signals the host that it is ready to begin data transfer by pulling the GPIO26 pin low.
The host load then initiates the data transfer by pulling the GPIO27 pin low. The complete protocol is
shown in Figure 2-19.
Figure 2-19. Parallel GPIO Boot Loader Handshake Protocol
1. The 28x device indicates it is ready to start receiving data by pulling the GPIO26 pin low.
2. The bootloader waits until the host puts data on GPIO [15:0]. The host signals to the 28x device that
data is ready by pulling the GPIO27 pin low.
3. The 28x device reads the data and signals the host that the read is complete by pulling GPIO26 high.
4. The bootloader waits until the host acknowledges the 28x device by pulling GPIO27 high.
5. The 28x device again indicates it is ready for more data by pulling the GPIO26 pin low.
This process is repeated for each data value to be sent.
Figure 2-20 shows an overview of the Parallel GPIO bootloader flow.
Figure 2-20. Parallel GPIO Mode Overview

Texas Instruments TMS320 2833 Series Specifications

General

Brand	Texas Instruments
Model	TMS320 2833 Series
Category	Controller
Language	English