Interphase Tech 4538 - Manual (Page 87)

Chapter 2: 4538 Power-Up Initialization
4538 Hardware Reference Manual 65
• APPC = 00: Address Parity pins used as local bus
• CS10PC = 01: – CS10/ – BCTL1 used as – BCTL1
• BCTLC = 01: – BCTL0 used as R/ – W and – BCTL1 used as – OE
• MMR = 11: External bus requests initially masked at boot, then
MMR = 00: No bus request masking once booted
• LPBSE = 0: LBPS/LGPL4 functions as LGPL4
The resulting register value is SIUMCR=0x4205C000.
Bus Transfer Error Registers (TESCR1 and L_TESCR1)
Since there is no parity checking on the 4538, data errors must be disabled (field DMD=1
in registers TESCR1 and L_TESCR1).
Memory Controllers
The PowerQUICC II includes sophisticated memory controller units: a General Purpose
Chip-select Machine (GPCM), three User Programmable Machines (UPMs) and two
SDRAM control machines. These units are used on the 4538 to control all the external
devices, except the PowerSpan, which is directly a 60x bus compatible device.
The memory controller unit to be used is defined bank per bank. Each bank is defined by
its Base Register (BRx) and its Option Register (ORx). The memory machine selection is
done in the Option register.
SDRAM Controller and SDRAM Device Initialization
For the SDRAM controller, a specific PowerQUICC II register (PSDMR for the 60x
SDRAM controller and LSDMR for the local SDRAM controller) is used to configure
operations pertaining to the SDRAM. This register includes several configuration fields
and one Operation field (OP). This Operation field must be used to generate all the special
accesses needed to initialize the SDRAM, such as the precharges, the refreshes, and the
SDRAM internal Mode register write. This will be useful for generating the complete
SDRAM initialization sequence.
To generate a special access, one must first set the OP field in the xSDMR register, and then
generate a dummy access to the SDRAM memory.
The sequence for SDRAM device initialization is as follows:
• Precharge all banks (OP=101)
Table 2-2. PowerQUICC II Memory Controller Machine Usage
Element Accessed Bank Memory Controller ORx Value BRx Value
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