UM10360 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
User manual Rev. 3 — 19 December 2013 619 of 841
NXP Semiconductors
UM10360
Chapter 32: LPC176x/5x Flash memory interface and programming
32.3.2.4 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 (0x13) is sent to
stop the flow of data. Data flow is resumed by sending the ASCII control character DC1
(0x11). The host should also support the same flow control scheme.
32.3.2.5 ISP command abort
Commands can be aborted by sending the ASCII control character "ESC" (0x1B). This
feature is not documented as a command under "ISP Commands" section. Once the
escape code is received the ISP command handler waits for a new command.
32.3.2.6 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 should 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.
32.3.2.7 RAM used by ISP command handler
ISP commands use on-chip RAM from 0x1000 0118 to 0x1000 01FF. The user could use
this area, but the contents may be lost upon reset. Flash programming commands use the
top 32 bytes of on-chip RAM. The stack is located at RAM top - 32. The maximum stack
usage is 256 bytes and it grows downwards.
32.3.2.8 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.
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