Hitachi 371
13.4
SCI Interrupt Sources and the DMAC
The SCI has four interrupt sources in each channel. transmit-end (TEI), receive-error (ERI),
receive-data-full (RXI), and transmit-data-empty (TXI). Table 13.13 lists the interrupt sources and
indicates their priority. These interrupts can be enabled and disabled by the TIE, RIE, and TEIE
bits in the serial control register (SCR). Each interrupt request is sent separately to the interrupt
controller.
TXI is requested when the TDRE bit in the SSR is set to 1. TXI can start the direct memory access
controller (DMAC) to transfer data. TDRE is automatically cleared to 0 when the DMAC writes
data in the transmit data register (TDR).
RXI is requested when the RDRF bit in the SSR is set to 1. RXI can start the DMAC to transfer
data. RDRF is automatically cleared to 0 when the DMAC reads the receive data register (RDR).
ERI is requested when the ORER, PER, or FER bit in the SSR is set to 1. ERI cannot start the
DMAC.
TEI is requested when the TEND bit in the SSR is set to 1. TEI cannot start the DMAC. Where the
TXI interrupt indicates that transmit data writing is enabled, the TEI interrupt indicates that the
transmit operation is complete.
Table 13.13 SCI Interrupt Sources
Interrupt Source
Description
DMAC Availability
Priority
ERI
Receive error (ORER, PER, or FER)
No
High
RXI
Receive data full (RDRF)
Yes
↑
TXI
Transmit data empty (TDRE)
Yes
↓
TEI
Transmit end (TEND)
No
Low
See section 4, Exception Processing, for information on the priority order and relationship to non-
SCI interrupts.
13.5
Notes on Use
Note the following points when using the SCI.
TDR Write and TDRE Flags: The TDRE bit in the serial status register (SSR) is a status flag
indicating loading of transmit data from the TDR into the TSR. The SCI sets TDRE to 1 when it
transfers data from the TDR to the TSR. Data can be written to the TDR regardless of the TDRE
bit status. If new data is written in the TDR when TDRE is 0, however, the old data stored in the
TDR will be lost because the data has not yet been transferred to the TSR. Before writing transmit
data to the TDR, be sure to check that TDRE is set to 1.
Summary of Contents for SH7095
Page 1: ...SH7095 Hardware User Manual ...
Page 23: ...12 Hitachi ...
Page 63: ...52 Hitachi ...
Page 77: ...66 Hitachi ...
Page 105: ...94 Hitachi Figure 5 14 Pipeline Operation when Interrupts are Enabled by Changing the SR ...
Page 127: ...116 Hitachi ...
Page 152: ...Hitachi 141 Figure 7 8 Example of 32 Bit Data Width SRAM Connection ...
Page 157: ...146 Hitachi Figure 7 13 Synchronous DRAM 32 bit Device Connection ...
Page 161: ...150 Hitachi Figure 7 15 Basic Burst Read Timing Auto Precharge ...
Page 167: ...156 Hitachi Figure 7 20 Burst Read Timing Bank Active Same Row Address ...
Page 168: ...Hitachi 157 Figure 7 21 Burst Read Timing Bank Active Different Row Addresses ...
Page 169: ...158 Hitachi Figure 7 22 Write Timing No Precharge ...
Page 170: ...Hitachi 159 Figure 7 23 Write Timing Bank Active Same Row Address ...
Page 180: ...Hitachi 169 Figure 7 29 Example of a DRAM Connection 32 Bit Data Width ...
Page 190: ...Hitachi 179 Figure 7 36 Example of Pseudo SRAM Connection 1 M pseudo SRAM ...
Page 191: ...180 Hitachi Figure 7 37 Example of Pseudo SRAM Connection 4 M pseudo SRAM ...
Page 209: ...198 Hitachi Figure 7 50 Master and Partial Share Master Connections ...
Page 231: ...220 Hitachi ...
Page 287: ...276 Hitachi ...
Page 307: ...296 Hitachi Note For a CPU writing H AA55 to FRC Figure 11 2 FRC Access Operation Write ...
Page 308: ...Hitachi 297 Note For an FRC reading from a CPU H AA55 Figure 11 3 FRC Access Operation Read ...
Page 333: ...322 Hitachi ...
Page 370: ...Hitachi 359 Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data ...
Page 371: ...360 Hitachi Figure 13 12 Sample Flowchart for Receiving Multiprocessor Serial Data cont ...
Page 395: ...384 Hitachi ...
Page 402: ...Hitachi 391 Figure 15 6 PLL Synchronization Settling Timing ...
Page 408: ...Hitachi 397 Figure 15 13 Bus Release Timing Slave Mode With PLL1 Off ...
Page 436: ...Hitachi 425 Figure 15 33 Synchronous DRAM Mode Register Write Cycle TRP 1 Cycle ...
Page 437: ...426 Hitachi Figure 15 34 Synchronous DRAM Mode Register Write Cycle TRP 2 Cycles ...
Page 449: ...438 Hitachi Figure 15 46 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL On ...
Page 454: ...Hitachi 443 Figure 15 51 DRAM CAS Before RAS Refresh Cycle TRP 1 Cycle TRAS 2 Cycles PLL Off ...
Page 461: ...450 Hitachi Figure 15 58 Pseudo SRAM Auto Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Page 462: ...Hitachi 451 Figure 15 59 Pseudo SRAM Self Refresh Cycle PLL On TRP 1 Cycle TRAS 2 Cycles ...
Page 467: ...456 Hitachi Figure 15 64 Pseudo SRAM Auto Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Page 468: ...Hitachi 457 Figure 15 65 Pseudo SRAM Self Refresh Cycle PLL Off TRP 1 Cycle TRAS 2 Cycles ...
Page 471: ...460 Hitachi Figure 15 68 Interrupt Vector Fetch Cycle PLL On No Waits ...
Page 472: ...Hitachi 461 Figure 15 69 Interrupt Vector Fetch Cycle PLL Off No Waits ...
Page 473: ...462 Hitachi Figure 15 70 Interrupt Vector Fetch Cycle 1 External Wait Cycle ...
Page 474: ...Hitachi 463 Figure 15 71 Address Monitor Cycle ...
Page 490: ...Hitachi 479 B 2 Register Chart ...