I disassembled a similar (it could be the same) box - I think it came out of a Hyundai Excel '95. It has a '537 cpu. There was also a couple of custom ics that the code seems to do a lot of work with. It seemed to read, process the write specific blocks of data. It is definitely a Bosch design, but made under license by a Korean company.

Here's the first bit of it....

WDTREL  equ	086h
PCON	equ	087h

DPSEL	equ	092h

IEN0	equ	0a8h
IEN1	equ	0b8h
IEN2	equ	09Ah
;
;		UART1
;
S1CON	equ	09bh
S1BUF	equ	09ch
S1REL	equ	09dh

IP0		equ	0a9h

IRCON	equ	0c0h

CCEN	equ	0c1h
CCL1	equ	0c2h
CCH1	equ	0c3h
CCL2	equ	0c4h
CCH2	equ	0c5h
CCL3	equ	0c6h
CCH3	equ	0c7h
CCL4	equ	0ceh
CCH4	equ	0cfh
CC4EN	equ	0c9h
CRCL	equ	0cah
CRCH	equ	0cbh
TL2		equ	0cch
TH2		equ	0cdh
;
;		a/d converter
;
ADCON0	equ	0d8h
ADDAT	equ	0d9h
DAPR	equ	0dah
ADCON1	equ	0dch
;
;		capture/compare
;
CTCON	equ	0e1h

CML0	equ	0d2h
CMH0	equ	0d3h
CML1	equ	0d4h
CMH1	equ 0d5h
CML2	equ	0d6h
CMH2	equ	0d7h

CML3	equ	0e2h
CMH3	equ	0e3h
CML4	equ	0e4h
CMH4	equ	0e5h
CML5	equ	0e6h
CMH5	equ	0e7h
CML6	equ	0f2h	 	;not used
CMH6	equ	0f3h		;not used
CML7	equ	0f4h		;not used
CMH7	equ	0f5h		;not used

CMEN	equ	0f6h
CMSEL	equ	0f7h


P4		equ	0e8h
P5		equ	0f8h
;
;		arithmetic unit
;
MD0		equ	0e9h
MD1		equ	0eah
MD2		equ	0ebh
MD3		equ	0ech
MD4		equ	0edh
MD5		equ	0eeh
ARCON	equ	0efh


INJ_DISABLE	equ	02bh   		 ;has bits to disable individual injectors

			org	2eh
			ds	8  			 ;temp area for sensor calcs??

			org	38h
			ds	1  			 ;coolant temp
			
			org	78h
			ds	1  			 ;injector1
			ds	1			 ;injector2
			ds	1			 ;injector3
			ds	1			 ;injector4			

			org 09ah
			ds	1			 ;air flow * 0.625
			ds	1			 ;air flow * 0.625 /8
			
			org	0a6h
			ds	1			 ;air flow sample count
			ds	3			 ;air flow accumulator (24bit) hi,mid,low
			ds	2			 ;air flow value hi,low


;-------------------------------------------------------------------------------
;
;		Xram locations (we're not too sure what's i/o and what's ram )
;
;
;-------------------------------------------------------------------------------
			org		0xf830
			ds		6	  	 ;->0x2e			
			org		0xf84b
			ds		5	  	 ;->0x2f			
			org		0xf8ca
			ds		5	  	 ;->0x2e coolant temp sesnor
			org		0xf8cf
			ds		5	  	 ;->0x2e air temperature sensor
;-------------------------------------------------------------------------------
;
;
;	disassembly of the bosch ecu for the hyundai excel 95
;	air flow
;	sequential injection
;	wasted spark (dual coil) 4 cylinder
;	uses siemens 80c537cpu methinks
;
;
;	Port 1
;	P1.0 cc0,int#3 capture enabled
;	P1.1 cc1,int#4
;	P1.2 100hz pwm? cc2
;	P1.3 100hz pwm? cc3
;	P1.4 cam angle input int#2/cc4
;	P1.5 check engine lamp
;	P1.6 injector 5??
;	P1.7 injector 6??
;
;	Port 3
;	P3.0 SPI data in
;	P3.1 SPI clock
;	P3.2 extint0
;	P3.3 speed sensor input int1
;	P3.4
;	P3.5
;	P3.6 WR
;	P3.7 RD
;

;	Port 4
;	P4.0 injector 1
;	P4.1 injector 2
;	P4.2 injector 3
;	P4.3 injector 4
;	P4.4 output??
;	P4.5 cm5 output?
;	P4.6 idle speed motor
;	P4.7 idle speed motor
;
;	P5.0 ccm0..
;	P5.1
;	P5.2
;	P5.3
;	P5.4
;	P5.5
;	P5.6
;	P5.7 diagnotic request input 0=request
;
;
;
;	Port 7 A/D
;	P7.0 throttle position
;	P7.1 battery volts ~70mV/count 18v=5v. 12v=3.3v (scale 3.6)
;	P7.2
;	P7.3 coolant temp
;	P7.4 air flow input
;	P7.5
;	P7.6 
;	P7.7 oxy sensor (input voltage times 2 methinks)
;
;	PORT 8 A/D
;	P8.0 air temp
;	P8.1 terminal 40??
;	P8.2
;	P8.3
;
;-------------------------------------------------------------------------------
;	reset
0000 02 00 9E     LJMP	009EH
;	exint0
0003 02 20 00     LJMP	2000H

0006 02 02 02
0009 02 02
;	 timer0 o/f
000B 02 20 08     LJMP	2008H
000E 02
000F 02 02 02
0012 02 02
;	 exint1
0013 02 20 2B	  LJMP	202BH
0017 02 02
0019 02 02
;	 timer1 o/f
001B 02 20 3B  	  LJMP	203BH
001E 02
001F 02 02 02
0022 02 
;	 serial0
0023 02 20 4B	  LJMP	204BH

0026 02 02 02
0029 02 02
;	 timer2
002B 02 20 53	  LJMP	2053H
002E 02
002F 02 02 02
0032 02 02 02
0035 02 02 02
0038 02 02 02
003B 02 02 02
003E 02 02 02
0041 02 02
;	 a/d converter
0043 02 20 5B	  LJMP	205BH
0046 02
0047 02 02 02
004A 02
;	 exint2
004B 02 20 63	  LJMP	2063H
004E 02 02
0050 02 02 02
;	 extint3
0053 02 20 6B     LJMP	206BH
0056 02 02 02
0059 02 02
;	 extint4
005B 02 20 7B	  LJMP	207BH
005E 02
005F 02 02 02
0062 02
;	 extint5
0063 02 20 83     LJMP	2083H
0066 02 02 02
0069 02 02
;	 extint6
006B 02 20 93	  LJMP	2093H
006E 02
006F 02 02 02
0072 02 02 02
0075 02 02 02
0078 02 02 02
007B 02 02 02
007E 02 02 02
0081 02 02
;	 serial1 
0083 02 20 9B	  LJMP	209BH
  		
0087 02 02 02
008A 02 02 02
008D 02 02 02
0090 02 02 02
0093 02 02 02
0096 02 02 02
0099 02 02 
;	 compare timer o/f
009B 02 20 A3	   LJMP		 20A3H		;RETI
;-------------------------------------------------------------------------------
;
;	things start here
;
;-------------------------------------------------------------------------------
009E E5 A9        MOV	A,IP0
00A0 A2 E6        MOV	C,ACC.6			;get WDTS										
00A2 92 D5        MOV	PSW.5,C
00A4 D2 BE        SETB	IP.6   			;wdt
00A6 02 20 AB     LJMP	20ABH

Good luck with the disassembly - its hard work, but worth it. You will learn many things.