ELECTRONIC CONTROLLER TO BE CONNECTED TO PROGRAM TOOL

摘要

A first external tool (10A) serially connected to an electronic controller (20A) through a pair of communication lines (LANH, LANN) applies a high voltage (Vaa) higher than a normal control voltage (Vcc) to the communication line (LANH) when a program is written. The electronic controller (20A) recognizes connection of the first external tool (10A) by a comparison circuit (212A) for monitoring a received voltage and a write-mode determination circuit (218A), initializes a microprocessor (200), and receives and stores an total control program (TCPRG) in a program memory (204A) based on a content of a boot program memory (201). During an operation of the electronic controller (20A), the external tool (10A) is removed and the high voltage (Vaa) is not applied to the communication line (LANH). Therefore, the electronic control apparatus is not erroneously placed in the write mode.

主权项

1. An electronic controller to be connected to a program tool comprising,
a control microprocessor for controlling driving of an electric load externally connected through an output interface circuit in accordance with an operating state of a sensor externally connected through an input interface circuit and a content of an input/output main control program (CPROG) which is a part of a total control program (TCPRG) stored in an electrically readable and writable non-volatile program memory; and a first external tool comprising:
a source memory having the total control program (TCPRG) written therein; anda transfer microprocessor for transferring and writing the total control program (TCPRG) to the program memory, the electronic controller and the first external tool being serially connected to each other, wherein: the serial connection uses a local area network (LAN) transceiver in which a master-station driver and a master-station receiver of the first external tool and a slave-station receiver and a slave-station driver of the electronic controller are connected to each other by a pair of communication lines (LANH, LANN); the pair of communication lines (LANH, LANN) are each a general-purpose communication line which is serially connectable to at least a second external tool replacing the first external tool; the control microprocessor further comprises:
a RAM memory for computation processing;a non-volatile boot program memory, which is one of a part of an area of the program memory and a memory connected after division; anda data memory for storing one of a control constant to be variably set and a control constant including apart of a control program, the data memory being one of apart of an area of the program memory and a memory connected after division; the boot program memory stores in advance a transfer control program (TPRG) for transferring and writing the total control program (TCPRG) through the LAN transceiver; the first external tool further comprises:
a control power supply for supplying a control voltage (Vcc) to the master-station driver and the master-station receiver; anda high-voltage power supply for supplying a high voltage (Vaa) to at least one of the pair of communication lines (LANH, LANN) in accordance with a switching signal (MOD) generated by the first external tool before the total control program (TCPRG) is transferred,the high voltage (Vaa) being higher than the control voltage (Vcc) and equal to or lower than a withstanding voltage at which the LAN transceiver operates normally; when the total control program (TCPRG) is transferred from the first external tool to be written to the electronic controller, the high voltage (Vaa) is applied to one of the pair of communication lines (LANH, LANN) at least until the control microprocessor recognizes a program write mode; the electronic controller further comprises a comparison circuit for determining whether or not a signal voltage transmitted by the communication lines (LANH, LANN) exceeds at least the control voltage (Vcc); when the comparison circuit detects a high voltage exceeding the control voltage (Vcc), a write-mode signal (WM) is generated by a write-mode determination circuit while the control microprocessor is initialized to be restarted by a reset-pulse generation circuit, and the restarted control microprocessor recognizes a write mode based on the write-mode signal (WM) and receives the total control program (TCPRG) transmitted from the first external tool by referring to the boot program memory to transfer the total control program (TCPRG) to be stored in one of the program memory; and the high-voltage power supply is one of blocked and excluded with respect to the second external tool, and the second external tool writes the control constant to the data memory based on a content of a telecommunication control program (TPRGU) which is another part of the total control program (TCPRG).