Semiconductor data processing device, time-triggered communication system, and communication system

Abstract

The variation of the timing of starting interrupt processing in response to a timer interrupt request is reduced regardless of the condition of processing of other interrupts. A semiconductor data processing device incorporated in each of plural electronic control devices coupled to a network for time-triggered communication system is provided with a central processing unit, a communication control circuit and an interrupt control circuit. The communication control circuit has a local time timer for use in time-triggered communication and issues, based on time counting by the local time timer, a timer interrupt request for time-triggered communication. When a timer interrupt request for time-triggered communication is received, the interrupt control circuit performs control to cause the central processing unit to delay, by a predetermined reservation time, starting the interrupt processing to be performed in response to the timer interrupt request.

1 - 18 . (canceled) 
     
     
         19 . A time-triggered communication system, comprising:
 a plurality of electronic control units which, by being coupled to a bus, configure a network and which perform transmission/reception operation in synchronization with a common time used in the network, each of the electronic control units comprising
 a transmission unit configured to perform frame transmission; 
 a reception unit configured to perform frame reception; 
 a local time timer configured to perform timer operation based on a local time specific to each electronic control unit; 
 a time synchronization control unit which adjusts the local time timer based on a difference between a time when a frame is expected to be received and a time when the frame is received; 
 a storage unit which stores a communication schedule specifying a frame transmission/reception procedure to be performed in a periodic communication cycle and setting information associated with the communication schedule; and 
 a control unit which, by causing the local time timer and the time synchronization control unit to operate based on the communication schedule and the setting information, controls a communication operation of the electronic control unit performed using the transmission unit and the reception unit, 
   wherein the control unit comprises
 a central processing unit which controls communication operation by executing a command; and 
 an interrupt control circuit which performs interrupt control to cause the central processing unit to perform processing responding to an interrupt request, 
   wherein the local time timer generates a timer interrupt request for time-triggered communication based on time counting performed based on the setting information associated with the communication schedule, and   wherein the interrupt control circuit performs control such that, when a timer interrupt request for time-triggered communication is received, the central processing unit in response to the timer interrupt request delays, by a predetermined reservation time, starting interrupt processing.   
     
     
         20 . A communication system comprising:
 a plurality of electronic control units coupled to a network and which perform communication via the network at a predetermined time,   wherein at least one of the plurality of electronic control units includes a semiconductor device comprising
 a central processing unit; 
 an interrupt control circuit; 
 a communication control circuit; and 
 a timer circuit, 
   wherein the timer circuit detects arrival of the predetermined time to perform communication and provides a notification to the interrupt control circuit,   wherein, in response to the notification received from the timer circuit, the interrupt control circuit provides an interrupt notification to the central processing unit,   wherein, at the predetermined time, the communication control circuit performs communication via the network, and   wherein, when the interrupt control circuit receives, after receiving a notification from the timer circuit and before the predetermined time is reached, another notification, the central processing unit is inhibited from performing processing in response to a different interrupt notification resulting from the another notification received by the interrupt control circuit.   
     
     
         21 . The communication system according to  claim 20 ,
 wherein, when, after receiving a notification from the timer circuit and before the predetermined time is reached, a different interrupt notification is received from another circuit, the interrupt control circuit inhibits the different interrupt notification from being transmitted to the central processing unit.   
     
     
         22 . The communication system according to  claim 20 ,
 wherein the interrupt control circuit has a time counting circuit and, when the predetermined time has been counted by the time counting circuit after a notification is received from the timer circuit, provides an interrupt notification to the central processing unit.   
     
     
         23 . The communication system according to  claim 20 ,
 wherein the interrupt control circuit has a register in which an amount of time to be counted after a notification is received from the timer circuit until the predetermined time is reached can be set.   
     
     
         24 . The communication system according to  claim 20 ,
 wherein the timing of notification from the timer circuit is set by the communication control circuit.   
     
     
         25 . The communication system according to  claim 20 ,
 wherein the communication system and the plurality of electronic control units are automobile-mounted.