14- April- 2013    The enhanced game launcher has the ability to browse and launch games directly from the WOS ( World of Spectrum ) ftp server. It requires the latest versions of the operating system and server applet as well as the 7za.exe command line archiver.   12- April- 2013      Due to supply shortage and a significant price escalation it has become unfeasible to include a SD card with every 'Interface 1bis'. The selling price was reduced accordingly.    The programs that used to be copied to the SD cards, as part of the interface's tests, can be downloaded from: games , utilities.   7- April- 2013      An issue affecting the integrity of the interface’s operating system was identified. At power-up the contents of the battery backed-up SRAM chip may be corrupted, due to spikes on the 5V supply line.     The extent to which corruption may occur differs largely, depending on the state of the Spectrum's power supply, both the external PSU and the internal voltage regulator circuits as well as on the method of connecting / disconnecting the power: by inserting / removing the PSU’s plug from the Spectrum’s power socket or by using a switch mains socket; but even from one SRAM chip to another.     The problem was not noticed in time because the units were tested only on a modified Spectrum, powered by a PC PSU.     In order to rectify this fault, a through-hole mounted radial aluminium electrolytic tank capacitor needs to be added to the interface in the position marked on the image to the right.     The recommended value range is from 100 µF to 1500 µF at a working voltage of 6.3 to 50 V. The lead pitch can be of 2.5 or 3.5 mm while the maximum operating temperature is irrelevant.    For best results, the solder mask should be scratched off from the vias on both sides and enough solder applied to fill the holes.    The capacitor should be mounted at a height of about 2 mm over the board to avoid  contact with the 4B pin of the edge receptacle. The space underneath should be filled with hot glue in order to improve rigidity.    The procedure described above applies to boards of the first lot marked: IF1BIS4B01. All further units will be pre-fitted with the tank capacitor.    Because the integrity of the SRAM contents cannot be unconditionally insured under all imaginable circumstances, a facility was devised to allow the instantaneous restoration of the operating system even in cases when the ZX Spectrum crashes or freezes.    Starting with lot 2 boards, marked IF1BIS4B02, the de-bouncing MCU and the CPLD were reprogrammed in such a way that pushing the button for longer than 2.5s resets the ZX Spectrum with the ‘Shadow ROM’ paged in, and thus triggers the reloading of the SRAM contents from the server or even from the SD card, if it was prepared, by copying the operating system to the last 64 sectors of its logical drive 1, using the 'SYS.ZZP' utility.      Users of lot 1 boards, experiencing SRAM contents corruption problems, are entitled to these rectifications free of charge, including return shipping costs.      Appologies for the inconvenience. |
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