ST92F150-EMU2 STMicroelectronics, ST92F150-EMU2 Datasheet - Page 123

• Manufacturer Part Number: ST92F150-EMU2
• Description: BOARD EMULATOR FOR ST9 SERIES
• Manufacturer: STMicroelectronics
• Series: ST9-EMU2r
• Type: Microcontrollerr

Specifications of ST92F150-EMU2

• Contents: ST9 Visual Debug IDE, ST9 HDS2V2 Mainboard, Probe, Sockets, Adapters, Power Supply,Cables & Documentation
• For Use With/related Products: ST9 MCUs
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 497-3101

DMA TRANSACTIONS (Cont’d)
When selecting the DMA transaction with memory,
bit DCPR.RM (bit 0 of DCPR) must be cleared.
To select between using the ISR or the DMASR reg-
ister to extend the address, (see Memory Manage-
ment Unit chapter), the control bit DAPR.PS (bit 0
of DAPR) must be cleared or set respectively.
The DMA transaction Counter must be initialized
with the number of transactions to perform and will
be decremented after each transaction. The DMA
Address must be initialized with the starting ad-
dress of the DMA table and is increased after each
transaction. These two registers must be located
between addresses 00h and DFh of the Register
File.
Once a DMA channel is initialized, a transfer can
start. The direction of the transfer is automatically
defined by the type of peripheral and programming
mode.
Once the DMA table is completed (the transaction
counter reaches 0 value), an Interrupt request to
the CPU is generated.
Figure 58. DMA Between Memory and Peripheral
n
PAGED REGISTERS
PERIPHERAL
DCPR
DAPR
DATA
IDCR
IVR
ST92F124/F150/F250 - ON-CHIP DIRECT MEMORY ACCESS (DMA)
FFh
F0h
EFh
E0h
DFh
REGISTER FILE
TRANSACTION
REGISTERS
REGISTERS
COUNTER
ADDRESS
SYSTEM
PAGED
DMA TRANSACTION
DMA
DMA
When the Interrupt Pending (IDCR.IP) bit is set by
a hardware event (or by software), and the DMA
Mask bit (IDCR.DM) is set, a DMA request is gen-
erated. If the Priority Level of the DMA source is
higher than, or equal to, the Current Priority Level
(CPL), the DMA transfer is executed at the end of
the current instruction. DMA transfers read/write
data from/to the location pointed to by the DMA
Address Register, the DMA Address register is in-
cremented and the Transaction Counter Register
is decremented. When the contents of the Trans-
action Counter are decremented to zero, the DMA
Mask bit (DM) is cleared and an interrupt request
is generated, according to the Interrupt Mask bit
(End of Block interrupt). This End-of-Block inter-
rupt request is taken into account, depending on
the PRL value.
WARNING. DMA requests are not acknowledged
if the top level interrupt service is in progress.
000000h
000100h
SERVICE ROUTINE
TRANSFERRED
END OF BLOCK
ISR ADDRESS
INTERRUPT
ALREADY
MEMORY
DATA
VECTOR
TABLE
TABLE
DMA
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