UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
437 of 1269
NXP Semiconductors
UM10503
Chapter 20: LPC43xx SD/MMC interface
20.6.32 Current Host Descriptor Address Register (DSCADDR)
20.6.33 Current Buffer Descriptor Address Register (BUFADDR)
20.7 Functional description
20.7.1 Power/pull-up control and card detection unit
Signal pull-up resistors can be enabled for the SD pins via the SCU by enabling the
pull-up for the pads. The approximate pull-up value for a pin is about 50 kOhm. For
designs that need to support legacy MMC cards in open-drain mode, an external pull-up
controlled
with a general purpose output and FET will be needed for the CMD line.
Slot power can be controlled with the SD_POW pin and the SD_VOLT[2:0] pins. It is
recommended that the slot power regulator is enabled and disabled via the SD_POW pin,
which can be directly controlled with bit 0 of the Power enable register (PWREN).
Use of the SD_VOLT[2:0] pins is optional and not needed in a design with a single power
supply sourcing the card slot.
8
NIS
Normal Interrupt Summary Enable. When set, a normal
interrupt is enabled. When reset, a normal interrupt is
disabled. This bit enables the following bits: IDINTEN[0] -
Transmit Interrupt IDINTEN[1] - Receive Interrupt
0
9
AIS
Abnormal Interrupt Summary Enable. When set, an
abnormal interrupt is enabled. This bit enables the
following bits: IDINTEN[2] - Fatal Bus Error Interrupt
IDINTEN[4] - DU Interrupt IDINTEN[5] - Card Error
Summary Interrupt
0
31:10
-
Reserved
Table 327. Internal DMAC Interrupt Enable Register (IDINTEN, address 0x4000 4090) bit
description
Bit
Symbol
Description
Reset
value
Table 328. Current Host Descriptor Address Register (DSCADDR, address 0x4000 4094) bit
description
Bit
Symbol
Description
Reset
value
31:0
HDA
Host Descriptor Address Pointer. Cleared on reset. Pointer
updated by IDMAC during operation. This register points to
the start address of the current descriptor read by the
SD/MMC DMA.
0
Table 329. Current Buffer Descriptor Address Register (BUFADDR, address 0x4000 4098) bit
description
Bit
Symbol
Description
Reset
value
31:0
HBA
Host Buffer Address Pointer. Cleared on Reset. Pointer updated
by IDMAC during operation. This register points to the current
Data Buffer Address being accessed by the SD/MMC DMA.
0