Nvram; Sram; Serial Ports; Figure 2-4. Board Serial Port Architecture - IBM PPC750FX User Manual

Evaluation Board Manual
PPC750FX Evaluation Board Preliminary

2.9 NVRAM

The board provides 32KB of non-volatile RAM. This memory is attached to the system controller device
interface, and is accessed using chip select DevCS3. This particular type of non-volatile ram uses magnetic
core technology and is referred to in the board schematics as FRAM. It does not require any battery power to
maintain its contents.

2.10 SRAM

The PPC750FX evaluation board provides 1MB of permanently mounted SRAM. This memory interfaces to
the system controller. Access to this memory by the processors is through the system controller. Address
space for SRAM is shared with Flash memory. See Flash Memory on page 22 for details on how the address
space can be configured.
In addition to the SRAM on the board, there are 256KB of addressible SRAM integrated in the system
controller module.

2.11 Serial Ports

The board utilizes an Exar ST16C2552 DUART to provide two 16550 compatible UARTs. The DUART is
attached to the device interface of the system controller, and is accessed using chip select DevCS2. Each
UART provides four interface signals (Tx, Rx, DSR, DTR) and is connected to an RJ11/12 connector.
Both serial ports are clocked by the same 3.68MHz oscillator provided on the board.
The Multi-Protocol Serial Controllers in the system controller are not supported on the PPC750FX evaluation
board.

Figure 2-4. Board Serial Port Architecture

ST16C2552
RJ11/12 Sockets
Dual UART
1 (A)
1 (Right)
2 (B)
2 (Left)
Board Design 750FXebm_ch2.fm
Page 24 of 115 June 10, 2003