AN2687 Freescale Semiconductor / Motorola, AN2687 Datasheet - Page 9

• Manufacturer Part Number: AN2687
• Description: BLDC Fan Control using the MC68HC908QT2
• Manufacturer: Freescale Semiconductor / Motorola

Overshoot and
Undershoot Filtering
MOTOROLA
For the 5-pin ICP interface, an adapter is used to connect the required signals
from the MON08 interface. For connection to the ESPGMR08, a cable is
provided for the connection.
To achieve a jumper-free configuration when connecting for ICP, the following
components were added: R4, R5, D2, D3, and R3. Resistors R4 and R5
provide the logic high or low to meet the monitor mode entry conditions. D2, D3
and R3 are used for the separation between PTA0 and IRQ pins and to avoid
the high voltage feeding into the target IRQ pin.
The programming software is the PROG08SZ.exe from P&E. For the 5-pin ICP
interface, select Class I. For the 16-pin standard MON08 interface, select
Class V for Cyclone or Class VII for Multilink. The ICP supports erase, program,
and verify of the FLASH memory in the MCU.
In both the evaluation and reference demos, additional capacitors and diodes
are added to filter any higher voltage spikes. On the evaluation demo board,
C3, C4, D3, and D4 filter out the overshoot and undershoot of the coil of the
BLDC motor. In the reference demo board, C3, C4, D2, and D3 do the same
filtering function.
Freescale Semiconductor, Inc.
Figure 9. BLDC Fan Evaluation Demo Board, ICP Connection with
BLDC Fan Control using the MC68HC908QT2
For More Information On This Product,
Go to: www.freescale.com
ESPGMR Serial Programmer
PART 2: HARDWARE DESIGN
AN2687/D
9