
UM10413
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
220 of 268
NXP Semiconductors
UM10413
MPT612 User manual
25.5.7 ISP flow control
A software XON/XOFF flow control scheme is used to prevent data loss due to buffer
overrun. When the data arrives rapidly, the ASCII control character DC3 (stop) is sent to
stop the flow of data. Data flow is resumed by sending the ASCII control character DC1
(start). The host must also support the same flow control scheme.
25.5.8 ISP command abort
Commands can be aborted by sending the ASCII control character "ESC". This feature is
not documented as a command in the "ISP Commands" section. Once the escape code is
received, the ISP command handler waits for a new command.
25.5.9 Interrupts during ISP
The boot block interrupt vectors located in the boot block of the flash are active after any
reset.
25.5.10 Interrupts during IAP
The on-chip flash memory is not accessible during erase/write operations. When the user
application code starts executing, the interrupt vectors from the user flash area are active.
The user must either disable interrupts, or ensure that user interrupt vectors are active in
RAM and that the interrupt handlers reside in RAM before making a flash erase/write IAP
call. The IAP code does not use or disable interrupts.
25.5.11 RAM used by ISP command handler
ISP commands use on-chip RAM from 0x4000 0120 to 0x4000 01FF. The user could use
this area, but the contents can be lost upon reset. Flash programming commands use the
top 32 bytes of on-chip RAM. The stack is at RAM top
32. The maximum stack usage is
256 bytes and it grows downwards.
25.5.12 RAM used by IAP command handler
Flash programming commands use the top 32 bytes of on-chip RAM. The maximum stack
usage in the user allocated stack space is 128 bytes and it grows downwards.
25.5.13 RAM used by RealMonitor
The RealMonitor uses on-chip RAM from 0x4000 0040 to 0x4000 011F. The user could
use this area if RealMonitor based debug is not required. The flash bootloader does not
initialize the stack for RealMonitor.