AN2442 Freescale Semiconductor / Motorola, AN2442 Datasheet - Page 5

• Manufacturer Part Number: AN2442
• Description: Booting the MSC8102 Device Through TDM
• Manufacturer: Freescale Semiconductor / Motorola

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4.1 Block Transfer Message
Perform the Block Transfer of Code and Data
The boot master device writes blocks of code and data into the memory of one or more MSC8102
devices. The MSC8102 implements a block transfer protocol to ensure that the boot master sends the
message to the target MSC8102 device and writes the code to the specified memory location. The block
transfer protocol also ensures correct message transmission by performing cyclic redundancy check
(CRC). The block transfer protocol implements the exchange of data and control code using two types of
messages: a block transfer message (BTM) and a block transfer acknowledge (BTAM) message.
A BTM contains blocks of code or data that are written to the MSC8102 memory (see Table 2).
The code shown on the left side of Figure 5 is broadcast to all MSC8102 devices connected to the boot
master via TDM. The code writes 1024 bytes of 0xAA and 512 bytes of 0x99 to memory locations
0x1010000 and 0x2010200, respectively. This code must be formatted as a BTM so that the boot master
can transmit it to the slave MSC8102 device via TDM. The BTMs of each set of code are shown on the
right side of Figure 5. The first four bytes consist of the preamble to indicate the start of the message.
Notice that 0x11 is the first byte sent. The next byte contains a value of 0xFF to indicate that the message
is being broadcast to all MSC8102 devices. The next byte contains a value of 0x00 to indicate that this is
the first message in the sequence. The next byte contains a value of 0x00 to indicate that this message is
not the last message in the sequence. The next three bytes contain a value of 0x000400 to indicate the size
of the payload (1024 bytes) that convert to a size of 0x400 bytes. The next four bytes indicate the
Size (Bytes)
Up to 2
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1
1
1
3
4
2
2
Freescale Semiconductor, Inc.
Block Transfer Message
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For More Information On This Product,
Name
HCRC
PLDS
DCID
PRM
CRC
PLD
SN
EB
DA
Go to: www.freescale.com
Table 2. Block Transfer Message Structure
CHIP_ID or 0xFF
0x00 to 0xFF
0x00 or 0xFF
0x44332211
0 to 2
Value
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Preamble. Indicates the start of the message. The first byte
sent is 0x11.
Destination CHIP_ID. Identifies the target MSC8102 slave
device to accept this message. DCID = 0xFF broadcasts the
BTM to all MSC8102 devices connected to the boot master.
Sequence Number modulo 256. Indicates the sequence
number of the BTM. The boot master generates a unique SN
for every BTM sent in a TDM boot session.
End Block. EB = 0xFF indicates the last BTM. After the last
message, all SC140 cores jump to address 0x0 of their M1
memory.
Payload Size. Indicates the size in bytes. PLDS must be
divisible by 2.
Destination Address. Indicates the destination address for the
payload in the slave MSC8102 memory. For valid addresses,
refer to the SC140 core internal memory map chapter in the
MSC8102 Reference Manual. Addresses
0x01076E00–0x01076FFF are reserved and cannot be used.
CRC-16 of PRM, DCID, SN, EB, PLDS and DA. The HCRC
field is a 16-bit CRC represented by x
Payload. Specifies the data to be written to the destination
address (DA).
CRC-16 of PLD. The CRC field is a 16-bit CRC represented by
x
16
+ x
Perform the Block Transfer of Code and Data
15
+ x
2
+ 1.
Description
16
+ x
15
+ x
2
+ 1.
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