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ML51/ML54/ML56
Sep. 01, 2020
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ML51/M
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Tec
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Manual
development or the end product needs firmware updating in the hand of an end customer, the
hardware programming mode will make repeated programming difficult and inconvenient. ICP method
makes it easy and possible without removing the microcontroller from the system. ICP mode also
allows customers to manufacture circuit boards with un-programmed devices. Programming can be
done after the assembly process allowing the device to be programmed with the most recent firmware
or a customized firmware.
There are three signal pins,
RST
̅̅̅̅̅̅
, ICPDA, and ICPCK, involved in ICP function.
RST
̅̅̅̅̅̅
is used to enter
or exit ICP mode. ICPDA is the data input and output pin. ICPCK is the clock input pin, which
synchronizes the data shifted in to or out from MCU under programming. User should leave these
three pins plus V
DD
and GND pins on the circuit board to make ICP possible.
Nuvoton provides ICP tool for ML51/ML54/ML56 Series, which enables user to easily perform ICP
through Nuvoton ICP programmer. The ICP programmer developed by Nuvoton has been optimized
according to the electric characteristics of MCU. It also satisfies the stability and efficiency during
production progress. For more details, please visit Nuvoton 8-bit Microcontroller website:
80C51 Microcontroller Technical Support
6.3.3
On-Chip-Debugger (ICE)
Functional Description
6.3.3.1
The ML51/ML54/ML56 Series is embedded in an on-chip-debugger (OCD) providing developers with a
low cost method for debugging user code, which is available on each package. The OCD gives debug
capability of complete program flow control with eight hardware address breakpoints, single step, free
running, and non-intrusive commands for memory access. The OCD system does not occupy any
locations in the memory map and does not share any on-chip peripherals.
When the OCDEN (CONFIG0.4) is programmed as 0 and LOCK (CONFIG0.1) remains un-
programmed as 1, the OCD is activated. The OCD cannot operate if chip is locked. The OCD system
uses a two-wire serial interface, OCDDA and OCDCK, to establish communication between the target
device and the controlling debugger host. OCDDA is an input/output pin for debug data transfer and
OCDCK is an input pin for synchronization with OCDDA data. The
RST
̅̅̅̅̅̅
pin is also necessary for OCD
mode entry and exit. The ML51/ML54/ML56 Series supports OCD with Flash Memory control path by
ICP writer mode, which shares the same three pins of OCD interface.
The ML51/ML54/ML56 Series uses OCDDA, OCDCK, and
RST
̅̅̅̅̅̅
pins to interface with the OCD
system. When designing a system where OCD will be used, the following restrictions must be
considered for correct operation:
1.
RST
̅̅̅̅̅̅
cannot be connected directly to V
DD
and any external capacitors connected must be removed.
2. All external reset sources must be disconnected.
3. Any external component connected on OCDDA and OCDCK must be isolated.
Limitation of OCD
6.3.3.2
The ML51/ML54/ML56 Series is a fully-featured microcontroller that multiplexes several functions on
its limited I/O pins. Some device functionality must be sacrificed to provide resources for OCD system.
The OCD has the following limitations:
1. The
RST
̅̅̅̅̅̅
pin needs to be used for OCD mode selection.
2. The OCDDA pin is physically located on the same pin P5.0. Therefore, neither its I/O function nor
shared multi-functions can be emulated.
3. The OCDCK pin is physically located on the same pin as P5.1. Therefore, neither its I/O function
nor shared multi-functions can be emulated.
4. When the system is in Idle or Power-down mode, it is invalid to perform any accesses because
parts of the device may not be clocked. A read access could return garbage or a write access might
not succeed.