Abstract: A data transfer controlling device of a direct memory access controller (DMAC) type includes a transfer number data storage, a transfer number updating decrementer, a data setter for setting predetermined initial data in the transfer number data storage, a terminal counter with a decrementer or an area counter with a decrementer, a memory address register, an address updating section, and a DMA execution control section. The number of times of transfer for the subsequent DMA transfer is automatically set when the number of DMA transfers to be successively executed in response to each DMA transfer request has been completed. Immediately thereafter, the DMA transfer is repeated in response to the subsequent DMA transfer request. When the DMA transfer has been completed to the final data in the DMA transfer source region of a memory, it is placed in an inhibited state. Thus, DMAC can respond to the DMA transfer request issued from a peripheral device at a high speed.

Abstract: A data transfer controller for transferring data between a memory and a peripheral unit enhances the efficiency of the DMA transfer by performing data transfer a predetermined number of times for each transfer request from the peripheral unit. The data transfer controller comprises a first register for storing address information for accessing a source area storing data to be transferred, a second register for storing first information relative to a number of data units ready to be transferred, and a third register for storing second information relative to a number of times by which a data transfer is performed in response to each transfer request from the peripheral unit. A data transfer from the source area to a destination area is performed a number of times designated by the second information in response to each transfer request. A transfer completion signal is generated when the number of data units transferred reaches the number designated by the first information.

Abstract: A microcomputer comprises a central processing unit, a watchdog timer generating a watchdog timer processing request when an overflow occurs in the watchdog timer, and an interrupt controller processing as a non-maskable interrupt the watchdog timer processing request generated by the watch timer. The central processing unit generates a preset signal to the watchdog timer at a beginning of execution of another interrupt processing by the central processing unit, so as to preset the watchdog timer. The interrupt controller responds to the preset signal for cancelling the watchdog timer processing request generated by the watchdog timer in a period of time of retaining the watchdog timer processing request by the interrupt controller.

Abstract: When DMA transfer for a DMA transfer area is completed, DMA transfer for the next area may be continuously executed or stopped. In addition to this, if there is a need to urgently stop DMA transfer being executed, DMA transfer can be immediately stopped without waiting for the end of DMA transfer currently executed. For continuous DMA transfer for a plurality of DMA transfer areas, the device may be provided with an authorization bit to authorize DMA transfer operation and a next area authorization bit to authorize DMA transfer for the next area and the contents in the next area authorization bit are set to the DMA authorization bit when the terminal counter which counts the number of DMA transfer data reaches the predetermined value due to decrement. Depending on the contents in the DMA authorization bit, DMA transfer may be continued or stopped when the next DMA transfer request is generated.

Abstract: In an interrupt controller, interrupt processing mode indication circuits are provided for each interrupt request circuit for storing interrupt processing mode information, and priority level indication circuits are provided for each interrupt request circuit, for storing acknowledgement order information. A search information generating circuit is provided each for generating interrupt processing mode search information and priority order search information. A search information comparison circuit detects the state of the interrupt request circuit provided for each interrupt request memory circuit, and compares the processing mode information and the acknowledgement order information with the interrupt processing mode search information and priority order search information.

Abstract: A data transfer controller for controlling DMA data transfer between a memory area and a peripheral unit. The data transfer controller has a first register which stores address information relative to a predetermined address of the memory area. A DMA control unit uses the first register and a second register to perform the DMA data transfer between the memory area and the peripheral unit. The data transfer controller also has a third register for storing data used for accessing the memory area of the DMA transfer. An updater is used to update the contents of the third register whenever a memory access uses the third register and is different from a memory access associated with data transfer between the memory area and the peripheral unit. Finally, a counter changes the contents of the third register in one direction whenever the data transfer between the memory area and the peripheral unit is performed.

Abstract: A port output controller for use in a microcomputer for outputting data to a plurality of output terminals in real time, includes a latch circuit for latching data being outputted to the output terminals and a buffer register for storing data to be outputted to the output terminals next to the data being outputted to the output terminals. A timer counter counts an elapsed time after the next data has been latched in the latch circuit and causes the next data stored in the buffer register to be latched into the latch circuit when the counted elapsed time becomes a predetermined data outputting period of time.

Abstract: A serial clock generating circuit is configured to frequency-divide an input clock having a frequency which is a number times a serial data transfer rate, so as to generate a serial clock in phase with a received serial data. The serial clock generating circuit comprises an edge detection circuit for detecting a level change of a received serial data so as to generate a level change signal. Three registers stores different set values, and a latch latches one of the different set values. A decrementer decrements the value of the latch in response to each input clock, and a memory circuit holds an arbitrary value for defining a phase deviation discrimination area. A comparison circuit compares the value stored in the memory circuit with the value of the latch at each one input clock, and generates a coincidence signal when a coincidence is obtained.

Abstract: A serial clock generating circuit for generating a serial clock in phase with a clock included in a received serial data on the basis of an input clock having a frequency N times of a serial data transfer rate of the received serial data, comprises an edge detector for detecting a level transition of the received serial data so as to generate a level transition detection signal, and a counter for counting the input clock. A first comparison register is provided for comparing a count value of the counter with a first programmable predetermined value at each one counting operation of the counter, so as to generate a first coincidence signal when the count value of the counter is coincident with the first programmable predetermined value.

Abstract: A data processor comprises an interrupt processing request controller receiving processing requests from peripheral devices for generating an interrupt request. An execution unit has a first mode of executing the interrupt processing in accordance with a user's program and a second mode of executing the interrupt processing in accordance with a microprogram while maintaining an internal condition concerning execution of a program. The controller operates to selectively inhibit the execution of the interrupt processing in the first mode, but to basically allow the execution of the interrupt processing in the second mode.