X1-005 - testing

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

Moderators: B00daW, Moderators

Post Reply
krzysiobal
Posts: 636
Joined: Sun Jun 12, 2011 12:06 pm
Location: Poland

X1-005 - testing

Post by krzysiobal » Thu Feb 13, 2020 11:31 am

Pin 1 - PRG A18
Pin 24 - V Battery (direct connector to positive battery terminal)
Pin 25 - RAM VCC
Pin 32 - goes low for the whole duration of read/write cycle when adress in 0x6000 .. 0x7FFF

lidnariq
Posts: 9008
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: X1-005 - testing

Post by lidnariq » Thu Feb 13, 2020 12:48 pm

Quickly checking a few other X1-005 boards, I noticed that there's something weird going on in J9100240A: http://bootgod.dyndns.org:7777/profile.php?id=1764

The resistors and diode are connected as:
+5V---1.5k---pin 24---1.0k---gnd
+5V---330---gnd
+5V---|>|----pin 25

Why would they bother providing a specific bias voltage on pin 24? In some other (battery-less) boards they just connect pin 24 to ground. Does the RAM not work if pin 24 is grounded?
Is there a battery voltage detection bit somewhere?

NesCartDB knows of the following X1-005-using PCBs:
J9100240A, no battery, pin 24 biased, pin 25 supplied via diode
P3-33A, battery, diode doing something unrelated?
P3-034A, battery, diode from battery to pin 25
P3-034-B, battery, diode from battery to pin 25
P3-034-C, battery, diode from battery but via to pin 25 is concealed in photo
P3-036-1, supposedly a battery, prototype with rework
"KR-14", no battery, pin 24 grounded, pin 25 floating?
アシユラー, no battery, pin 24 grounded, pin 25 ... pulled down via resistor?

krzysiobal
Posts: 636
Joined: Sun Jun 12, 2011 12:06 pm
Location: Poland

Re: X1-005 - testing

Post by krzysiobal » Thu Feb 13, 2020 2:10 pm

RAM memory (if enabled), works no matter if pin 24 is disconnected or connected to GND. I need to check how much current the X1-005 sinks through pin 25, depending on the voltage on pin 24, that might answer the question how voltage on pin 24 affects that, however for non-battery version that should not matter much (but maybe it affects RAM timing)

Weirdly, in the PCBs equipped with battery, despite having place for second diode, SRAM is constantly powered from battery even if +5V is present.

Post Reply