Difference between revisions of "Category:83Plus:Ports:Unknown"

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(Removed excessive SEEMS and cleaned up a bit)
(Another mystery, revealed)
 
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===83+ & SE Calculator Ports===
 
===83+ & SE Calculator Ports===
−
'''Port 04:''' Writing:
+
* Bits 6, and 7: "Low battery" level is not known. It would be great if somebody with a finely-variable voltage DC power supply tested this. The values are probably controlled using external resistors, because the TI-84+CSE's lithium-ion battery operates at a completely different voltage level.
−
* Bit 3: always 0, doesn't seem to have any effect
+
−
* Bit 4: always 1, doesn't seem to have any effect, guessing leftover from 83 code
+
−
* Bit 5: always 1, guessing same as 83
+
−
* Bit 6: default 1, guessing same as 83
+
−
* Bit 7: Voltage level at which port 02 bit 0 flips, default 0
+
−
 
+
  
 
===SE Calculator Ports Only===
 
===SE Calculator Ports Only===
−
'''Port 0B:'''
+
'''Port 17:''' This always reads 0, and writing to it produces no apparent effect. It's a bit suspicious, because all the ports before it and after it have a purpose.
−
* Tied to the link assist on the SE calculators. Only written to in boot code where it receives B4.
+
  
−
'''Port 0C:'''
+
'''Ports 39 and 3A:'''
−
* Tied to the link assist on the SE calculators. Only written to in boot code where it receives B4.
+
* These ports seem to control GPIO pins, but exactly what those pins connect to is a mystery.
  
−
'''Port 0E:'''
+
'''Port 3B:''' Very like does nothing.
−
* Tied with swapping bank $4000. Before swapping pages this port should contain 00, otherwise data read from those pages may not be accurate.  
+
  
−
'''Port 0F:'''
+
'''Ports 3C-3F:'''
−
* Tied with swapping bank $8000. Before swapping pages this port should contain 00, otherwise data read from those pages may not be accurate.
+
* On DrDnar's TI-84+CSE, these read 78, yet on a TI-84+SE with the TA3 ASIC, they read 00.
−
 
+
−
'''Port 21:'''
+
−
* Although used as a hardware detection, it's more likely to be ram execution protection. See the talk page for more info. [[Talk:83Plus:Ports:21|Talk Page Port 21]]
+
−
 
+
−
'''Port 25:'''
+
−
* This port acts similarly to flash restriction port 22. Set to 16 by default. This is a [[Category:83Plus:Ports:By_Address:Protected|protected port]].
+
−
 
+
−
'''Port 26:'''
+
−
* This port acts similarly to flash restriction port 2223. Set to 32 by default. This is a [[Category:83Plus:Ports:By_Address:Protected|protected port]].
+
−
 
+
−
'''Port 2D:'''
+
−
* Only bits 0 and 1 can be altered, but no effect is apparent.
+
−
 
+
−
'''Port 2E:'''
+
−
* All bits can be altered but only 2 appear to have an effect. This port needs more information.
+
  
 
'''USB Ports:'''
 
'''USB Ports:'''
 
* All information concerning the USB ports will be handled [[83Plus:OS:84_Plus_USB_Information|here]].
 
* All information concerning the USB ports will be handled [[83Plus:OS:84_Plus_USB_Information|here]].
−
 
  
 
==Comments==
 
==Comments==
−
Other ports have unknown functions but are never written to, read from, or change in a significant way. Port 15 on the SE calculators has a value that does seem possible to change, but is not used directly. Other ports likely have no purpose at all.
+
Other ports have unknown functions but are never written to, read from, or change in a significant way, some likely have no purpose at all.
  
 
There is still quite bit unknown about the hardware, however the remainder is less significant to or can not be used by the average coder.
 
There is still quite bit unknown about the hardware, however the remainder is less significant to or can not be used by the average coder.

Latest revision as of 14:34, 12 August 2013


Synopsis

There are several ports that have not yet been totally solved. Here is a list of them and what information is available.


83+ & SE Calculator Ports

  • Bits 6, and 7: "Low battery" level is not known. It would be great if somebody with a finely-variable voltage DC power supply tested this. The values are probably controlled using external resistors, because the TI-84+CSE's lithium-ion battery operates at a completely different voltage level.

SE Calculator Ports Only

Port 17: This always reads 0, and writing to it produces no apparent effect. It's a bit suspicious, because all the ports before it and after it have a purpose.

Ports 39 and 3A:

  • These ports seem to control GPIO pins, but exactly what those pins connect to is a mystery.

Port 3B: Very like does nothing.

Ports 3C-3F:

  • On DrDnar's TI-84+CSE, these read 78, yet on a TI-84+SE with the TA3 ASIC, they read 00.

USB Ports:

  • All information concerning the USB ports will be handled here.

Comments

Other ports have unknown functions but are never written to, read from, or change in a significant way, some likely have no purpose at all.

There is still quite bit unknown about the hardware, however the remainder is less significant to or can not be used by the average coder.


Credits and Contributions

  • Tijl Coosemans
  • Dan Englender
  • James Montelongo
  • Michael Vincent

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