As some Tiny C2N Monitor buyers have found out, the LCD panel they received is not working as expected. Let me spend a few words here on where I believe the mess started.
Firstly, I bought all batches of red LCD panels from the same eBay seller, listed under the very same listing: http://www.ebay.co.uk/itm/111317541232
Contrary to common sense and expectations, the red LCD panels V1.1 I ordered in October 2015 and developed Tiny C2N Monitor with are incompatible with the red LCD panels the seller is shipping under the same eBay listing, now V2.1, despite the fact his listing’s pictures clearly read V1.1. Moreover, the latest red panels are different from the black panels V1.1 also often found on eBay.
In practice, I seem to have come across 3 different LCD panels all behaving differently due to the different memory addressing settings on the controller. This means they all require a different driver, especially when hardware scrolling is used, which is the case with Tiny C2N Monitor.
Community users seem to be are aware of the fact some of these LCD modules come with the wrong settings, as shown in a number of online forums, e.g. https://forum.pjrc.com/threads/25862-ILI9163C-128×128-TFT-driver
Quoting from the above post: “The maker of those display’s (a chinese for sure) forgot to set the hardware addressing for fix the memory map to a certain resolution (in this case 128 x 128) and leaved at 128 * 160 so this display showed big pixel addressing problems…”
I myself developed the firmware for these red LCD panels V1.1 circumventing the issue introduced by the manufacturer and have designed the hardware in a way that the LCD is oriented conveniently for users to read from it when connected to a Commodore 64.
I haven’t got the original product code for the red LCD module I developed Tiny C2N Monitor with, but it has a blue label on the LCD protection that I didn’t find elsewhere (other models have a dark green label) and reads “1.44′ SPI 128*128 V1.1” on the backside. If anybody has the product code for the red panel V1.1 with a blue label, it’d be great to know what it is.
As per other panels, I do have their product codes:
- old red panel (memory addressing for 128*160): ??, ??, ?? – reads V1.1 on the silkscreen
- black panel (addressing 128*128): 28021, A08D3, 1501012-819 – V1.1 on the silkscreen
- new red panel (addressing 128*160): 28022, A08D3, 151222-819 – V2.1 on the silkscreen
The new red panel V2.1 sold under the same listing as per above is behaving in a way that is in between the behaviour of the old red and black ones: Its mapping of physical memory to the display is simply opposite to V1.1 meaning that the extra 32 rows in the erroneous mapping now have to be dealt with in a different way.
In substance, neither 28021 nor 28022 will work fine with the standard Tiny C2N Monitor firmware, although eBay sellers seem to be naively selling 28022/V2.1 under the very same listing they used to sell the old red panel V1.1 under!
I adapted my firmware to work for 28021 and 28022: I’ve found out that both 28021 and 28022 are oriented differently compared to the old red panel and need a different initialization sequence (specifically the parameter provided to the memory access control command) in order for them not to display the output upside down compared to what Tiny C2N Monitor was meant to show using the red LCD panel V1.1.
However, the firmware on Tiny C2N Monitor cannot be easily updated once in the field. Therefore getting the right LCD module to work with Tiny C2N Monitor would be the simplest route.
I’ve started an eBay case with the seller of the LCD modules I bought, in order to express my dissatisfaction with them selling incompatible LCD modules under the same listing that clearly shows V1.1 in their pictures. I shall let you know how that goes.
At the same time I am approaching other eBay sellers asking specifically for the color of the label and version on their red LCD panels before ordering replacements for those buyers who got a kit with an incompatible panel.