SAF-C164SM Infineon Technologies, SAF-C164SM Datasheet - Page 260

• Manufacturer Part Number: SAF-C164SM
• Description: 16-Bit CMOS Microcontroller
• Manufacturer: Infineon Technologies

15.1
The C164CM enters BSL mode triggered by external configuration during a hardware
reset:
• when pin P0L.4 is sampled low at the end of an external reset (EA = ‘0’)
• when pin RD is sampled low at the end of an internal reset (EA = ‘1’).
In this case, the built-in bootstrap loader is activated independent of the selected bus
mode. The bootstrap loader code is stored in a special Boot-ROM, no part of the
standard mask ROM, OTP, or Flash memory area is required for this.
The hardware that activates the BSL during reset may be a simple pull-down resistor on
P0L.4 or RD for systems that use this feature upon every hardware reset. You may want
to use a switchable solution (via jumper or an external signal) for systems that only
temporarily use the bootstrap loader.
Figure 15-2 Hardware Provisions to Activate the BSL
The ASC0 receiver is only enabled after the identification byte has been transmitted. A
half-duplex connection to the host is therefore sufficient to feed the BSL.
Note: The proper reset configuration for BSL mode requires more pins to be driven
User’s Manual
Proposal for Internal Reset
(EA = '1')
besides P0L.4 or RD.
For an external reset (EA = ‘0’) bitfield SMOD must be configured as 1011
Section
For an internal reset (EA = ‘1’) pin ALE must be driven to a defined level, e.g.
ALE = ‘0’ for the standard bootstrap loader (see
P0L.4
RD
Entering the Bootstrap Loader
20.4.1).
~2 k
Ext.
Signal
Start
Boot
Proposal for Internal Reset
(EA = '0')
P0L.4
RD
~8 k
15-2
Ext.
Signal
Start
Boot
Section
Proposal for Combined Circuitry
P0L.4
RD
20.4.2).
C164CM/C164SM
~2 k
~8 k
Bootstrap Loader
Derivatives
V1.0, 2002-02
MCA04466
Ext.
Signal
Start
Boot
B
(see