Motorola IH5, MCPN750A manual Jtag/Cop, Bank a Flash Programming Enable

Block Diagram

The MCPN750A also contains four 16-bit Smart Voltage FLASH SMT devices (Intel Part #E28F800CVB70) that appear as FLASH Bank A to the Falcon chipset. The FLASH size for this bank is 4MB when 8Mbit devices are used. Only 32-bit writes are supported for this bank of FLASH. There is a jumper to tell the Falcon chipset where to fetch the reset vector. When the jumper is installed, the Falcon chipset maps 0xFFF00100 to these sockets (Bank B).

The onboard monitor/debugger, PPCBug, resides in the Boot Flash chips on the MCPN750A. PPCBug provides functionality for:

❏Booting the operating system

❏Initializing after a reset

❏Displaying and modifying configuration variables

❏Running self-tests and diagnostics

❏Updating firmware ROM

Under normal operation, the Flash devices are in “read-only” mode, their contents are pre-defined, and they are protected against inadvertent writes due to loss of power conditions. However, for programming purposes, programming voltage is always supplied to the devices and the Flash contents may be modified by executing the proper program command sequence. Refer to Intel Data Sheet 290539-004, dated December 1996 and/or to the PPCBug Firmware Package User’s Manual for further device-specific information on modifying Flash contents.

JTAG/COP

Connector J6 on the MCPN750A board provides access to the JTAG/COP interface on the MPC750 processor. The interface can be used to provide debug control and observation of the MPC750. Refer to Table 7-9 for pinout information.

Bank A Flash Programming Enable

No jumper is required on header J9. The FLASH programming for Bank A is permanently enabled with onboard resistors.

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