M32C8A Datasheet, PDF (156/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
14. DMACII
14.5 Chain Transfer
The chain transfer can be selected with the CHAIN bit in MOD.
The chain transfer is performed as follows.
(1) Transfer occurs in response to an interrupt request from a peripheral function and is performed according to
the contents of the DMACII index at the address specified by the interrupt vector. For one transfer request,
either a single transfer or burst transfer selected by the BRST bit in MOD occurs.
(2) When COUNT reaches zero, the interrupt vector in (1) is replaced with the address written in CADR1 and
CADR0. The end-of-transfer interrupt occurs after the replacement, if the INTE bit in MOD is set to 1.
(3) When the next DMACII transfer request is generated, the transfer is performed according to the contents of
the DMACII index specified by the interrupt vector which has been replaced in (2).
Figure 14.4 shows the relocatable vector and DMACII index when using the chain transfer.
For the chain transfer, the relocatable vector table must be located in the RAM.
Relocatable
Vector
INTB
RAM
Interrupt vector of the peripheral function triggering
DMACII request. Default value is BASE (a).
DMACII index (a)
BASE (a)
(CADR1,
CADR0)
BASE (b)
DMACII index (b)
BASE (b)
(CADR1,
CADR0)
BASE (c)
When COUNT reaches zero, the above interrupt
vector is replaced with BASE (b), which is the
address written in CADR1 and CADR0.
When the next request occurs, a transfer starts
according to the contents of the DMACII index at
BASE (b).
When COUNT reaches zero, the interrupt vector
is replaced wtih BASE (c).
Figure 14.4 Relocatable Vector and DMACII Index When using the Chain Transfer
14.6 End-of-Transfer Interrupt
The end-of-transfer interrupt can be selected with the INTE bit in MOD. Set the starting address of the end-of-
transfer interrupt routine in IADR1 and IADR0. The end-of-transfer interrupt occurs when COUNT reaches zero.
Rev.1.00 Jul 15, 2007 Page 139 of 352
REJ09B0385-0100