Dmac Examples; Dmac Example With External Bus; Figure 3-1: Setup Rom/Ram Area - Fujitsu FR Series Application Note
32-bit direct memory access
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- Application note (35 pages) ,
- Instruction manual (314 pages) ,
- Instruction manual (304 pages)
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3 DMAC Examples
EXAMPLES FOR DIRECT MEMORY ACCESS CONTROLLER
3.1 DMAC Example with External Bus
The following example demonstrates how to configure the DMAC channel 0 with external
transfer requests. Here the falling edge on DREQ0 pin triggers the DMAC transfer. Upon
such trigger the DMA transfers 1 block of data (which comprises of 4 words) from the
internal RAM to the external ram connected via external bus starting from address
0x20000000. The DTC is set as 4, hence after transferring such 4 blocks of data (in
response to 4 falling edges), the DMAC0 interrupt is generated. In the DMAC0 ISR the
source and destination array is compared. If there is any mismatch then 0xAA is ouput on
LEDs connected to Port 16, otherwise 0xFF is ouput on the LEDs.
In order to place the dst_buff[] at the external area starting from address 0x20000000,
the ROM/RAM area needs to be set up as below:
The above dialog box can be reached as mentioned below...
Project -> Setup Project -> Linker -> Disposition Connection -> ROM/RAM Area List -> Set
After doing this, the external bus should be configured using the Start91460.asm as below:
Enabling External Bus interface
;======================================================================================
; 4.8 External Bus Interface
;
The rest of the configuration is only applicable for devices with an external bus
;
interface.
;
If the device does not offer an external bus interface, the configuration can be
;
stopped at this point.
;=======================================================================================
;
#set
EXTBUS
;
; Note: This feature is not supported by every device. Please check the data sheet.
;
Following devices for example do not offer an external bus interface:
;
MB91467C, MB91465K, MB91463N, MB91465X.
;
;=======================================================================================
© Fujitsu Microelectronics Europe GmbH
DIRECT MEMORY ACCESS
Chapter 3 DMAC Examples
Figure 3-1: Setup ROM/RAM Area
ON
; <<< Ext. Bus on/off
- 19 -
MB91464A,
MCU-AN-300059-E-V11
The
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