TMPR3916 datasheet(69/225 Pages) TOSHIBA

69 / 225 page

Chapter 2 Memory Controller (MC)

Preliminary

2-20

2.6

MEMC Function

Channel functionality is specified by applying special values to Channel Control Registers. They must be

accessed using 32-bit cycles.

2.6.1

Channel Assignment

TMPR3916 contains the total of four multi-purpose memory controller channels.

The following chip-select signals are assigned to these channels:

Chip Enable Signal

Assigned to Channel

CS2

MEMC Channel 2

CS3

MEMC Channel 3

CS4

MEMC Channel 4

CS5

MEMC Channel 5 (Boot Channel)

Channel 5 is a special function channel and is used to boot the microprocessor from external devices

like SRAM, ROM or FLASH memories.

2.6.2

Channel 5 Boot Function

For the system boot procedure, it can be chosen, whether the system shall be booted from a 16 or 32

bit device.

This choice is made by connecting a pull-up or pull-down resistor to the A26/ BOOT16 pin. The

value of this pin is latched once during system startup on the rising edge of the reset signal, when the

EBIF data bus is tri-stated.

Value of A26 / BOOT16 Pin

on Rising Edge of Reset

Boot-function

Channel 5 is 32-bits wide at boot time

Channel 5 is 16-bits wide at boot time

2.6.3

Operational Modes

We can distinguish two operational modes depending on the types of memory connected to the

channels 2 to 5. These two operational modes lead to two different settings: Flash/SRAM setting and

Page Mode ROM setting.

2.6.3.1

Flash/SRAM setting

The SRAM and Flash memories cannot be accessed in page mode. Therefore some parameters

in the RCCRx (x = 2, 3, 4, 5) control registers assume a particular meaning.

The setting of bits RPM is always 00 (“Not configured for page mode”).

The RPWT is no longer used as a wait state parameter for second and following accesses in

burst mode. In non-page mode RPWT and RWT define together the wait time in the access to the

Flash or SRAM. The RWT represents the lower significant bits of the wait time parameter, while

RPWT represents the most significant bits.

TMPR3916 Datasheet(PDF) 69 Page - Toshiba Semiconductor

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