NXP Semiconductors LPC24XX UM10237 - Manual (Page 549)

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User manual Rev. 04 — 26 August 2009 549 of 792
NXP Semiconductors
UM10237
Chapter 20: LPC24XX SSP interface SSP0/1
6.7 SSPn Raw Interrupt Status Register (SSP0RIS - 0xE006 8018,
SSP1RIS - 0xE003 0018)
This read-only register contains a 1 for each interrupt condition that is asserted,
regardless of whether or not the interrupt is enabled in the SSPnIMSC.
6.8 SSPn Masked Interrupt Status Register (SSP0MIS - 0xE006 801C,
SSP1MIS - 0xE003 001C)
This read-only register contains a 1 for each interrupt condition that is asserted and
enabled in the SSPnIMSC. When an SSP interrupt occurs, the interrupt service routine
should read this register to determine the cause(s) of the interrupt.
Table 476: SSPn Interrupt Mask Set/Clear register (SSP0IMSC - address 0xE006 8014,
SSP1IMSC - 0xE003 0014) bit description
Bit Symbol Description Reset
Value
0 RORIM Software should set this bit to enable interrupt when a Receive
Overrun occurs, that is, when the Rx FIFO is full and another frame is
completely received. The ARM spec implies that the preceding frame
data is overwritten by the new frame data when this occurs. 0
1 RTIM Software should set this bit to enable interrupt when a Receive
Timeout condition occurs. A Receive Timeout occurs when the Rx
FIFO is not empty, and no has not been read for a "timeout period". 0
2 RXIM Software should set this bit to enable interrupt when the Rx FIFO is at
least half full. 0
3 TXIM Software should set this bit to enable interrupt when the Tx FIFO is at
least half empty. 0
7:4 - Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined. NA
Table 477: SSPn Raw Interrupt Status register (SSP0RIS - address 0xE006 8018, SSP1RIS -
0xE003 0018) bit description
Bit Symbol Description Reset Value
0 RORRIS This bit is 1 if another frame was completely received while the
RxFIFO was full. The ARM spec implies that the preceding
frame data is overwritten by the new frame data when this
occurs. 0
1 RTRIS This bit is 1 if the Rx FIFO is not empty, and has not been read
for a "timeout period". 0
2 RXRIS This bit is 1 if the Rx FIFO is at least half full. 0
3 TXRIS This bit is 1 if the Tx FIFO is at least half empty. 1
7:4 - Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined. NA