Backplane bus is documented at : https://allpinouts.org/pinouts/connectors/buses/ecb-bus/

Peripheral ports buzzed out on the board (all connect to a 74ls138N)

Z80SIO/0 /CE is 0x50 to 0x53 (A0 & A1 not decoded for /CE address)
					B/*A is on A0
					C/*D is on A1
Z80CTC /CE is 0x54 to 0x57 (A0 & A1 not decoded)
Z80PIO /CE is 0x4C to 0x4F (A0 & A1 not decoded)

// Ports written to and read from
// dumped from the onboard ROM

	                         in a,(04dh)
	                         in a,(050h)
       out (051h),a	       in a,(051h)
	                         in a,(052h)
	                         in a,(053h)

       out (055h),a
       out (056h),a	       in a,(056h)
       out (057h),a	       in a,(057h)
       out (080h),a	       in a,(080h)
       out (081h),a

       out (083h),a
       out (084h),a	       in a,(084h)
       out (085h),a	       in a,(085h)
	                         in a,(086h)
	                         in a,(087h)
	                         in a,(088h)
       out (089h),a	       in a,(089h)
       out (08ch),a
       out (08dh),a
       out (08eh),a
       out (08fh),a
       out (090h),a	       in a,(090h)
       out (091h),a	       in a,(091h)
       out (092h),a	       in a,(092h)
       out (093h),a	       in a,(093h)
       out (094h),a	       in a,(094h)
       out (095h),a	       in a,(095h)
       out (096h),a	       in a,(096h)
       out (097h),a	       in a,(097h)
       out (098h),a
       out (09ah),a
       out (09bh),a
       out (09ch),a
       out (09dh),a
       out (09eh),a
       out (09fh),a	       in a,(09fh)
       out (0a0h),a	       in a,(0e2h)
	                         in a,(0e3h)
	                         in a,(0f0h)
